One of my favorite topics back when I taught Botany 101 was plant oddities. A recent question on our Garden Professors’ discussion group on Facebook reminded me about cladophylls, like the one pictured below.
Cladophyll literally means “branch leaf.” Anatomically it’s a branch (it has nodes from which new stems, leaves, flowers, and even roots can arise), but it functions as a leaf. It’s the main site of photosynthesis in plants such as holiday cacti (Schlumbergera species). Like other cacti, they have reduced leaves and if you look closely at the photo, you can see the leaves as tiny hairs arising from the nodes at the end of the stem and along the sides.
But unlike cacti, these plants aren’t found in deserts, and their leaves are soft threads rather than the vicious sharp spines you’ll find in typical cacti. Instead, these are generally epiphytes in coastal mountains where humidity is relatively high. But root water is limited for epiphytes and these waxy cladophylls probably are adaptations against water loss. Their reduced leaves are immune to drought stress, unlike those of other succulents which appear only when water is plentiful.
As you might expect from their red, tubular flowers, holiday cacti are pollinated by hummingbirds in their native environment. Gardeners who have a sufficiently mild climate to grow these outdoors might be lucky enough to see them visited.
It’s been awhile since I wrote about, or recommended a blog I like which I often use as a source of something to share to The Garden Professors Facebook Page, so I thought I’d revisit the topic this month.
Add a friend, chef Michelle Fuerst, to provide recipes and there you have it.
Our goal is three-fold: to share the fascinating biology of our food plants, to teach biology using edible, familiar examples, and to suggest delicious ways to bring the plants and their stories to your table. To judge by the questions we are often asked at dinner parties (“What is an artichoke?” “Why is okra slimy?”), some curious eaters genuinely want to know which plant part they are eating and how its identity affects the characteristics of the food.
Plants and food? Tell me more! Well, espousing the view that ‘a person can learn a lot about plants through the everyday acts of slicing and eating them’, The Botanist in the Kitchen ‘is devoted to exploring food plants in all their beautiful detail as plants – as living organisms with their own evolutionary history and ecological interactions’.
I first learned about the blog back in 2015 from an article in Business Insider, linking to their post on the various foods we grow, that were bred from one species of plant …
Six vegetables you can find in any grocery store and which most people eat on a regular basis are actually all from this one plant. Over the last few thousand years, farmers have bred Brassica Oleracea into six “cultivars” that eventually became many of the vegetables we eat …
Some species have undergone the domestication process multiple times, and with some of these species, each domestication effort has focused on amplifying different structures of the plant, producing a cornucopia of extraordinarily different vegetables or fruits from the same wild progenitor. Such is the case with Brassica oleracea. The wild plant is a weedy little herb that prefers to grow on limestone outcroppings all around the coastal Mediterranean region.
So if you enjoy learning about plants we eat, and trying various recipes with them, be sure to follow the Botanist in the Kitchen via email.
Previous posts here on the other blogs I’ve recommended:
As we edge closer to spring it is time to start getting ready for the active growing season. Many gardeners kick off their gardening year early with indoor seed starting to prepare for the upcoming season.
Starting your own seeds is an excellent, and often economical way to prepare for your year of gardening. Whether you grow vegetables or flowers (or both), starting from seeds can offer many benefits. Of course, there are some dos and don’ts for getting the most mileage from your seed starting endeavors.
I recently connected with Joe Lamp’l, host of the Growing a Greener World show on public television and the more recent The Joe Gardener Show podcast to talk about advanced seed starting techniques and technology.
You can follow the link below to listen to the show on your computer, or find it on Stitcher or iTunes (links included on the show page, too). In addition to the podcast, the show page features extension notes on everything we chatted about with links to good reading materials.
Be economical. One of the great benefits of starting plants from seeds is saving money. A packet of several (even hundreds) of seeds is often around the same price you’ll pay for one plant at the garden center. Of course, if you go out and splurge on the fancy (and expensive) seed-starting systems you see in your garden store or favorite catalog you may end up investing more than you planned. Instead of fancy seed starting trays or peat pellets and pots, use low-cost or recycled items such as takeout containers or shallow disposable aluminum baking pans to start your plants. Remember that if you are reusing containers, especially ones that have had plants grown in them before, that sterilization is key in reducing disease. Thoroughly wash the containers, then dip in a solution of 10% household bleach (1 part bleach : 9 parts water) to disinfect. There are some horticultural disinfectants out there, but bleach is usually the easiest for home gardeners to get since you can pick it up at the local store.
Start seeds in clean, sterile seed-starting mix. This is one area where I don’t skimp. You’ll want to use a sterile mix that is primarily made of peat or coconut coir. It is lightweight and pathogen free and also low in fertility, so you will be less likely to lose plants to such issues as damping off (a fungus that rots the seedlings off at the base). Using regular potting mix may work, but increases your chances of such issues. Plus, seeds are equipped with enough nutrients to make it to their first set of true leaves before they need anything from the soil. I know that some sources say to use mixes with compost in them, but unless you know 100% that the compost got hot enough to kill all pathogens (140 degrees plus for several days) you could be introducing diseases to your plants that could affect them in the seedling stage or in the future.
Once the seedling has its first set of true leaves (the second leaves that appear), you should transfer it to an individual container/cell/pot with regular potting soil. At this point, the plant will need to have nutrients from the soil to grow healthy. You’ll want to loosen the plant from the seedling mix (I use a chopstick) and lift it by the leaves (not the stem). Temperature control is key.
Heat is usually the most important factor in coaxing your seeds to germinate, so placing your newly sown seeds in a warm (around 75 degrees F) place will help them germinate faster. Fast germination is key for making sure you get the optimal number of seeds sprouting. However, moving the seedlings to a cooler place (around 65 degrees) after they’re germinated will make them grow sturdier and keep them from getting thin and leggy. Most people laugh when I tell them, but one great warm place to start seeds is on top of the refrigerator.
Light is necessary for good plant growth. Most seeds don’t require light until they get their first true leaves, but after that you’ll want light to keep your plant healthy. Some people are lucky to have a good, sunny (usually south facing) window with plenty of light. Otherwise you’ll need to invest in some lighting. The most economical option is a basic shop light fixture from the hardware store. You can buy plant lights, or full spectrum lamps for it, but if they prove too difficult (or expensive) to find, use a regular warm fluorescent and cool fluorescent bulb to get the right light spectra. You’ll want light on for about 16 hours per day. If you are using a window, be sure to turn the plants regularly to keep them from
growing in one direction. As LED lights become less expensive, many home gardeners are checking them out for home seed starting. You can use a full spectrum white LED bank, but plants primarily use red and blue light so you can also find high-intensity LED banks for plant production that are blue and red (makes purple!). Some research is emerging that a tiny bit of green light helps growth, so some newer systems are incorporating a touch of green, too.
Don’t get started too early. Look at the packet for the number of days/weeks before last frost to start your seeds. If you start them too early, you could end up with spindly, leggy plants or ones that have grown too large for their containers. Even if you have good lighting, your plants will not thrive being cooped up in the house too long.
What about fertilizer? Up until the first set of true leaves, seedlings don’t need much in the way of fertility. When they’re put in larger containers or cells, a good potting mix (usually containing some type of fertilizer or nutrients) will get you most everything you need….to a point. If you’re growing in small containers, say those cell packs where you have very limited soil, you may find that you need to provide supplemental fertility after a few weeks. There’s only so many nutrients in that potting mix in small amounts, so if you are holding your plants for longer than, say, six weeks you may need to apply a water-soluble fertilizer or start off with a slow-release fertilizer. Larger containers, say a 3 or 4 inch pot, may have enough soil to have sufficient nutrients to get you to the point of transplanting.
This month’s National Geographic has a brief article from an ongoing study of the DNA profiles of urban honey. While we can all observe honeybees visiting flowers in our own gardens, until recently we could only assume what nectar they were collecting for honey production. This tantalizing snippet completely blew me away.
The study, undertaken by an entomologist who founded the Urban Beekeeping Laboratory and Bee Sanctuary, is sampling urban hives from major cities, including Boston, Portland (OR), New York, San Francisco, Seattle, and Washington DC. For each of these cities, National Geographic reports the top three plants for honeybees based on relative DNA levels.
Here’s what I found amazing about this research:
The top sugar sources are from TREES. Not wildflowers. We don’t see bees visiting trees as easily as we see them visiting flowers, so our perceptions are biased. Over 75% of the sugar used for urban honey is from trees.
The trees that are most popular for bee visitation are not necessarily native to those regions. Seattle bees, for instance, prefer linden and cypress trees, neither of which are part of the native coniferous forest. Likewise, the despised eucalyptus trees of San Francisco are one of the top three sugar sources.
You’ll notice that I didn’t use the word “nectar” in describing what bees are collecting. That’s because much of the sugar they are gleaning isn’t coming from flowers. It’s coming from sap-sucking insects like aphids that produce honeydew. Bees apparently collect honeydew as well as floral nectar.
Urban areas usually have higher plant diversity than rural areas, given the variety of woody and herbaceous plants that people use in their gardens and landscapes. The researchers speculate that this higher plant diversity may be one reason that urban hives are healthier and more productive than rural ones.
Many gardeners operate under the assumption that native plants are the best choice for gardens and landscapes. Though certain landscapes (like those undergoing ecological restoration) should only be planted with natives, there is no evidence-based reason that we shouldn’t be using non-invasive, introduced species as part of our planting palette. In fact, research has demonstrated that tree species nativity plays only a minor role in urban landscape biodiversity: most animals learn to use new resources in their environment. Honeybees, considered to be “super-generalists” insects, are demonstrating that in spades.
Greetings all, and good to be back in the saddle for the Garden Professors. It’s been a while since I’ve filled you in on my own personal gardening struggles (lots) and triumphs (few) as well as topics I think you’d be interested in. I’ve always appreciated the kind comments and good questions our readers pose, in response to my off-kilter posts and horrific punctuation.
I’m sure there is one BURNING question that long-time readers have:
I’m sure many readers have been at the receiving end of a cactus spine or Agave poke; the genus Puya makes Agaves look like stuffed animals. Fish hooks line the margins of each leaf, and cascade over the side of the pot. Therein lies the problem…
I’ve attempted to “go in” a couple of times, but even leather grilling gloves get snagged. Need really strong tongs (two sets?). I’m probably going to have to just bust the pot. She didn’t make it out to the deck this summer due to the awkward pot situation. Suggestions welcome, especially from anyone who has wrestled with one of these (and lived)!
Hybrid, heirloom, organic, non-GMO, natural….there’s lots of labels on those seed packets or plants you pick up at the garden center or from your favorite catalog. Since the seed-starting season is upon us, let’s take a minute to look at some of the information – and mis-information – you might find on those seed packets.
For a brief overview, here’s a short video segment I recently shot for the Backyard Farmer Show, a popular public TV offering for Nebraska Extension:
Hybrid vs. Heirloom vs. Open Pollinated
Just what is a hybrid anyway?
Simply put, a hybrid is a plant (or any living organism, technically) with two different parents. Take for example the Celebrity variety of tomato, which is very popular among home gardeners. In order to get seeds of Celebrity tomatoes, whoever produces the seeds must always cross two specific parent plants to get those specific seeds, called an F1 hybrid.
These parents have been developed through traditional breeding programs (read: the birds and the bees — no genetic engineering here) from many different crosses. Hybridization has occurred naturally ever since there were plants. Man has been directing this process throughout most of his agricultural history to get better crop plants. How else would we have many of the vegetables and fruits that we take for granted today?
Crops like corn have very little resemblance to its wild counterpart, many thanks to selection and even crossing of superior plants by humans over the centuries. University researchers and seed developers use this natural ability of plants to cross to direct the formation of new varieties that improve our ability to produce food.
What is an heirloom?
Perhaps the first question we should ask is, what is an open-pollinated seed? An open-pollinated variety is one whose genetics are stable enough that there is no need for specific parent plants, because the seeds produced from either self-pollination (as in the case of beans and tomatoes) or cross-pollination with the same variety will produce the same variety.
An “heirloom” plant is basically an open-pollinated plant that has a history, either through age (50-plus years) or through heritage (it has a family story).
Take for example the Mortgage Lifter tomato.
It was developed by a gentleman living in West Virginia (my native state -there are two competing stories as to who developed it). For all intents and purposes, the Mortgage Lifter started out as a hybrid, since the gardener in question developed the tomato by crossing many different varieties to find one that he liked. He sold so many of them to his neighbors that he was able to pay off the mortgage…thus its interesting moniker.
It just so happened that the genetics of this tomato were stable enough that its offspring had the same characteristics, so seeds could be saved. Therefore, it was technically an Open-Pollinated variety. Over time, the tomato became considered an heirloom because of both its age and unique story. This story has played out many times, in many gardens and in many research plots at universities.
There are some trying to revive the practice of plant breeding for the home gardener. If you’re interested, check out the book “Plant Breeding for the Home Gardener” by Garden Professor emeritus Joseph Tychonievich. Who knows? Maybe in 50 years we will be celebrating your plant as a distinctive heirloom.
So which is better – Heirlooms or Hybrids?
There are pros and cons to hybrid plants and heirlooms both, so there really isn’t an answer as to which one you should plant. It really boils down to personal choice. Hybrid plants tend to have more resistance to diseases and pests, due to the fact that breeders are actively trying to boost resistance. This means that there will be higher-quality produce fewer inputs. This is why hybrids are popular with farmers — nicer, cleaner-looking fruits with fewer pesticides. Many times hybrids are also on the more productive side, thanks to a phenomenon called hybrid vigor.
Heirlooms, on the other hand, help preserve our genetic diversity and even tell our cultural story. Heirlooms do not require a breeding program, so there is built-in resilience, knowing that we can produce these seeds well into the future with little intervention. But we do have a trade-off with typically less disease-resistance and less consistency on things like yield. Since they are open-pollinated, they are often a good choice for people who enjoy or rely on saving seeds from year to year.
GMO-Free or Non-GMO
As we have pointed out several times before, when it comes to seeds for home gardeners, the label of GMO-Free is largely meaningless and sometimes mis-leading. Whether or not you believe the prevailing science that shows that genetically engineered plants are safe for human consumption, you can rest assured that there are currently no genetically engineered seeds or plants available to home gardeners. Not on the seed rack at the box store nor your local garden center. Not in a catalog or online.
Here are two assurances to that statement: A majority of the things that you grow in the home garden don’t have a genetically engineered counterpart. Only
12 genetically engineered crops have been approved in the US, and only 10 of those are currently produced. Most of these are commodity crops that home gardeners would not even produce, such as cotton, sugar beet, canola, and alfalfa. A few more have counterparts that are grown by home gardeners, but are vastly different from those grown by commodity producers (soybeans vs. edamame soy). And some just aren’t that very widespread (there are some GE sweet corn cultivars and squash cultivars, but they aren’t widespread on the market).
So for the most part, there aren’t any “GMO” counterparts to the crops you’d grow in the home garden. They don’t exist.
The other assurance is that genetically engineered crops are not marketed or sold to home gardeners as a matter of business practice or law. In order to purchase genetically engineered seeds or plants, it is current practice in the United States that you must sign an agreement with the company that holds the patent stating that you will not misuse the crop or propagate it (and before we get into the whole intellectual property argument – plant patents and agreements like this have been around since the early 1900s – it isn’t new). So you know that you aren’t buying genetically engineered seeds since you aren’t being asked to sign an agreement. Plus, these companies make their money by selling large quantities of seeds, they just aren’t interested in selling you a packet of lettuce seeds for $2.
So since there aren’t any GMOs available to home gardeners, why do all these seed companies slap that label on their packets? Marketing, my dear! It started off with just a few companies, mainly using the label to compete in a crowded market. And fear sells. The label has spread to more and more companies as this fear and anti-science based marketing ploy has spread…both by companies who jumped on the fear bandwagon and by those who took so much harassment from the followers of the non-GMO crowd or they lost sales to people sold on the non-GMO label that they finally gave in. Unfortunately for some companies, slapping the non-GMO label on a product seems to give them permission to charge more, even if has no real meaning….so buyer beware.
Treated vs Non-Treated
Seed treatment usually involves the application of one or more pesticide such as a fungicide or insecticide to protect against pathogens or pests, mainly in the early stages of growth. A good example would be if you’ve ever seen corn, pea, or bean seeds at the local feed or farm store that are bright pink or orange in color. These seeds have been treated with a fungicide to offer short-term protection against damping off. Some crops are also treated with systemic insecticides, such as imidacloprid, to protect against insect damage. There’s been a big emergence of organic seed treatments, so treatment doesn’t necessarily mean the crop can’t be labeled organic.
Treated crops are most-commonly found at farm supply stores and aren’t generally marketed directly to home gardeners. You’ll likely not find them at most box stores or garden centers catering exclusively to gardeners. Many packets will specify whether they are non-treated or treated.
Organic and Natural
In seeds, the term Organic largely refers to seeds harvested from plants that were certified organic. Generally speaking, these seeds were produced on plants that received no synthetically produced fertilizers or pesticide sprays. However, it does not mean that the plants were not treated with pesticides. There’s a great misunderstanding about organic production – there are a number of pesticides and even seed treatments approved for use on organic crops. Typically, they are produced from a plant or microorganism extract, naturally occurring mineral, or other organic derivative. So organic does not equal pesticide free (on the seed rack or on the grocery shelf).
There are a few different levels of “organic,” too.
Sometimes small producers use the label in a general sense to mean that they follow organic practices, but aren’t certified. The process for certification is often onerous and costly for small producers, so they often opt to not get it. This is especially true for producers that market exclusively to a local clientele, like at the farmers market, where they can rely on their relationship with customers and reputation to speak for their practices. Some food companies may also use a simple “organic” label – either as a design choice, or because their product wouldn’t qualify for a certification.
“Certified organic” means that the producers practices have been certified to meet the requirements laid down by a certifying agency. A certifying agency could be a non-profit or a state department of agriculture. The requirements and practices vary from entity to entity.
For certified organic producers, a requirement for production is that all seeds or plant sources are organic. For home gardeners, I often question the need for organic seed, even if organic methods are followed. A quick literature search turned up no evidence that garden seeds contain pesticide residues. There’s been no evidence that plants translocate systemic pesticides to their seeds or fruits(Though it is impossible to prove a negative). Since seeds are located inside some sort of fruit, there would be little chance of residue on the seed from a pesticide application. And even if there was some sort of residue, it would be such a small amount in the seed that it would be so dilute in the mature plant that it would likely be well below any threshold of threat to human or wildlife health…or even measurability.
Personally, I may opt for the organic seed at home if it were the same price of the “conventional” on offer…but that organic label often includes a pretty good price differential. Knowing that there likely isn’t a huge difference in what is in the packages….my penny-pinching self will reach for the conventional, cheaper option.
And what about “natural.” That one’s easy….there is no recognized definition of natural by the USDA or any other body. Companies use that term to mean whatever they want it to mean….meaning that it is relatively meaningless in the grand scheme of things.
I was asked by Dr. Linda Chalker-Scott to look up some information in order to answer a recent comment and question on a previous post.
Paraphrased, the question is, “… are there any verifiable “organic” fertilizers that can be guaranteed to be made from 100 percent non-GMO sources.”
First off, let me state up front that the whole “Non-GMO” labeling effort is pure marketing. There is no evidence to suggest products that come from genetically engineered crops are any different than crops made from other plant breeding methods. The body of evidence in fact suggests they are as safe as their conventional counterparts, and have some excellent benefits to farmers and consumers from an economic and environmental standpoint.
Having gotten that disclosure out of the way, and assuming that price is not a factor, it turned out to be an interesting question to answer.
“USDA Certified Organic” fertilizers would be problematic, since there are exceptions to the organic standards, which allow manures fed GE crops to be used.
Similarly, oilseed meals like cottonseed, soybean meal, etc. also can be certified organic, even though they come from genetically engineered crops.
One possible alternative in that category is alfalfa meal, since genetically engineered alfalfa is currently grown on only 13.5% of alfalfa acreage, whereas in the case of cottonseed, soybean, sugar beet, and corn products, the rate of adoption of genetically engineered crops is well over 90% of U.S. acreage.
Only about 13.5 percent of harvested U.S. alfalfa acreage is genetically modified, compared to more than 90 percent of corn, soybeans, cotton, canola and sugar beets acres, according to a new USDA report that cites 2013 farmer surveys.
It appears likely the percentage of genetically engineered alfalfa will continue rising, though: Roughly one-third of newly seeded acreage planted that year was of a biotech variety resistant to glyphosate herbicides, USDA said.
Farmers have been slower to adopt genetically engineered alfalfa partly because it’s a perennial crop that stays in the ground for roughly five years, said Dan Putnam, an alfalfa extension specialist at the University of California-Davis.
It would be incumbent upon the buyer to ask, however, if the alfalfa meal came from a grower who does not use genetically engineered alfalfa, and whether or not the supplier of the alfalfa meal guarantees that.
MANURES FROM LIVESTOCK FED ONLY ORGANIC FORAGE
“Demeter USA” … the private certifying entity that guarantees “Biodyamic” preparations does require that any manures come from livestock fed only “USDA Certified Organic” feed. So manures that carry that seal should satisfy the question.
As an aside, here is Dr. Linda Chalker-Scott’s literature review of “Biodynamics” and why that certification has little science to recommend it.
Further, finding the product would be difficult, since it is primarily produced on-site at certified Biodyamic farms, and used there.
Next products that might qualify are seaweed, or kelp products. There are no genetically engineered seaweed/kelp products I’m aware of. However, there are real concerns about the sustainability of harvesting seaweed and kelp from the wild.
I can’t however, find any products available for the home gardener that are sourced from this effort. Still early.
So, when it comes to seaweed/kelp products, you’ll have to (again) ask a reputable supplier to answer the “sustainable” question.
In a similar vein, “Bat guano” products would also qualify as “non-genetically engineered”, but the sustainability question also comes into play. How is it harvested?
I can’t deny that it’s a great fertilizer, but if you want to use an organic fertilizer why not at least consider one that is renewable instead of one that is from a limited resource and which may cause harm to a unique ecological system?
Fertilizers made from by-products of the seafood and fish industries, assuming they don’t come from aquaculture farms, since the livestock feed for those operations could be sourced from genetically engineered crops, do have a history.
Two links (there may be others, but these seem sufficient for now), a comprehensive review of products (including fertilizers) from the Alaska seafood industry, put together by Oregon State University …
Fish Fertilizer Product Descriptions
Fertilizers are characterized by their Nitrogen-Phosphorous-Potassium content (N-P-K). Therefore all fish material will have some fertilizer value since fish contain protein which is Nitrogen,
the bone contains Phosphorous and the flesh and bone contain Potassium. Generally, fish products are re-allocated to fertilizer use for any number of reasons including quality too poor for feeding, volume too small to convert to fishmeal and oil, and an available agricultural market in the vicinity of the waste material.
In an effort to help the Michigan fish processing industry find better solutions to handle fish processing waste materials, a project was initiated to determine the viability of composting fish waste.
There is a mineral product called Chilean Nitrate or Nitrate of Soda that is mined from a desert in northern Chile that is allowable for use under the standards for organic production in the U.S. However, it is not allowed for use under Canadian, or international organic standards, and a change to prevent its use under U.S. standards is still pending. Up until 2012, this was the wording for its use.
Sodium nitrate, also known as chilean nitrate, cannot account for more than 20 percent of the N requirements of organic crops in the United States.
Its use is also prohibited by the International Federation of Organic Agriculture Movements (IFOAM) and most other standards for organic production outside the United States.
The expiration of the current notation will effectively mean that sodium nitrate may be used in organic crop production without a specific restriction on the amount used: however, producers must continue to comply with all requirements of the soil fertility and crop nutrient management practice standard.
Although the National Organic Standards Board (NOSB) recommended that sodium nitrate become a completely prohibited nonsynthetic substance, the NOP has not issued rule-making to carry out this recommendation as of yet.
You’d be saving yourself the cost of fertilizer, saving the environmental cost of shipping the fertilizer you might otherwise purchase, saving water, and you’d have something unique to tell your gardening friends about. Win – win situation as far as I’m concerned.
In summary, I don’t buy into any of the fear-based marketing of products that come from genetic engineering. There may be (at this time) sources of alfalfa meal that do not come from genetically engineered sources.
Biodynamic manures certified by Demeter USA require that the animals be fed only “USDA Certified Organic” feed, but will be difficult to come by. Seaweed/Kelp and Bat guano products would qualify, but have major sustainability questions about them. Lots of potential with seafood/fish by products, and finally … a personal possible solution.
Many thanks to Emanuel Farrow, a consultant to both conventional and organic farmers, who helped point me in the right direction and provided important fact checking expertise for this post.
The Garden Professor’s collective resolution is to have at least one new blog post a week for 2018. So I’m kicking things off with a little fact checking on the claims made for a product that’s “a complete ecosystem in a bottle.” The company touts its strong connection to science (“our products revolve around biology”). There is a long list of ingredients and claims – way too much for one post. We’ll start with the first four this week.
Ingredient claim #1: “Chitin/chitin degrading Bacillus: Chitin is a natural polymer that is found in crustaceans, such as crabs, lobsters, shrimp and oysters as well as other organisms, such as insects, worms and fungi. When added to the soil ecosystem, chitin (also referred to as chitosan) promotes the growth of chitin-degrading bacteria. These bacteria, in turn, create a hostile environment for pathogenic fungi and parasitic nematodes. Chitin also acts directly on plants to promote tissue repair and disease resistance.”
Fact check #1: A couple of technical points: oysters don’t have chitin. And they’re not crustaceans. They are MOLLUSKS. They have shells with CALCIUM. And chitosan is not the same thing as chitin. It’s an industrially produced material that comes from chitin.
Chitin is indeed found in arthropods, which include crustaceans and insects. Now, most of us don’t have crabs, lobsters and shrimp roaming our landscape, but we do have insects. Lots of them. They produce a lot of chitin when they molt and when they die. Do you really think we need to add more chitin for Bacillus to consumer? I sure haven’t seen any science supporting that practice.
What about the Bacillus species that degrade chitin? Well, if you’ve got insects in your landscape, you can bet you’ve got microbes that break down chitin as well. Otherwise you’d be up to your garden boots in chitin carcasses. So why do we need to add more bacteria?
Finally, there’s no evidence that chitin applied to plants in the landscape has any effect whatsoever. You might get responses in the lab, and chitosan (not chitin) might have some direct application. But like many other elicitors, you have to get it inside the plant to have a cellular effect. And plants are particularly adept at keeping things like decomposing bug bits outside of their tissues.
Ingredient claim #2: “Compost tea: The disease suppressive characteristics of compost have long been known and therefore the liquid extracts from compost, known as compost teas are being use to battle plant disease while stimulating plant growth. Beneficial organisms including bacteria (primarily from the genera Bacillus, Pseudomonas, and Penicillium) along with some yeast and fungi form a physical barrier against disease causing agents and provide a competitive environment in which the pathogenic species lose out. In addition, compost teas stimulate plant growth, translating into a healthier plant, which is more resistant to attack from disease. Compost teas have shown effectiveness in the control of late blight, grey mold, downy and powdery mildew, fusarium wilt, and apple scab among many others.”
Fact check #2. Just because compost has disease suppressing characteristics doesn’t mean that water leaching through it will have the same. We’ve been hearing for years that compost tea suppresses disease. Where’s the definitive research? It’s a topic I’ve been following for nearly two decades and there’s still nothing that’s consistently effective. (Another technical point here: it’s illegal to make pesticidal claims of a product that’s not registered for that use. Company lawyers may want to review that.)
There are many species of bacteria, including the ones mentioned, that form protective and beneficial biofilms on plant tissues such as fine roots. You can find these bacteria in compost and other sources of organic material – that’s their food source. You won’t find many of them in compost tea.
I’d love to see evidence of anything stimulating plant growth other than plant growth regulators (or hormones as they’re sometimes called).
Aren’t marketers getting tired of compost teas yet? I’m getting tired of hearing about them. I reviewed the science about them 10 years ago and haven’t seen anything to warrant an update.
Ingredient claim #3: “Essential oils: or essences they are called, are highly concentrated substances extracted from various parts of aromatic plants and trees. Essential oils are combined with other carrier oils and teas for stabilization. Essential oils are used against plant pests and disease by interfering with their reproduction and feeding habits while protecting beneficial predatory organisms.”
Fact check #3: Essential oils have no documented benefit when applied outdoors. They can be effective in closed spaces, like homes and greenhouses, but they dissipate quickly outside. What I really want to see, however, is the mechanism by which oils can identify – and actually protect! – beneficial insects while killing pests. (Hey, lawyers…we’ve got another pesticidal claim here…)
Ingredient claim #4: “Streptomyces griseoviridis: Is a naturally occurring soil bacteria. The microbe deprives pathogenic fungi of living space and nourishment by colonizing roots in advance of fungi. In addition the microbe secretes various enzymes and metabolites which inhibit pathogenic growth. Streptomyces griseoviridis has been shown to promote the growth and yield of all plants. Streptomyces griseoviridis is used for the prevention of root and stem rot, Pythium, Rhizoctonia, Helminthosporium, Sclerotinia, among others.”
Fact check #4: While this is a naturally occurring soil bacterium, it’s not clear where it naturally occurs. EPA information states it was first isolated in Finland from peat bogs. Is this something we should be introducing to our own soils? Its effectiveness in disease control and plant performance is sporadic and confined primarily to greenhouse application on crop plants. The diseases listed are common in greenhouses, but not necessarily in gardens and landscapes (presumably because there are natural controls outdoors in healthy soils). There is certainly nothing to support its use in gardens and landscapes, especially considering that many native, beneficial bacterial species can colonize plant roots and act as a protective biofilm.
This weekend I received a link to a Maryland gardening column with the intriguing title “Murder by Mulch.” My correspondent was concerned that her planned use of arborist wood chip mulch was going to cause problems. I assured her that it would not – but then spent some time looking at the column and putting it through CRAP analysis (credibility, relevance, accuracy, and purpose). It’s a skill that I encourage everyone – not just gardeners – to develop. (You’ll need to read the linked column to understand the context of my comments below.)
So we’ll start with credibility. The column is not a peer-reviewed resource, but then again neither is this blog. The author is a retired Extension specialist with research publications in compost science. That would seem to fit well with the topic. We’ll give it the benefit of doubt for now.
How about relevance? Is this information relevant to the use of mulches in home landscapes? Absolutely.
Is this accurate information? At this point the column starts to fall apart. Let’s start with the photo (you’ll need to go to the linked column to see it). This tree didn’t die because of mulch, but because it had girdling roots – the result of planting trees improperly. Furthermore, there is no mechanism I can think of in which mulch would “strangle” a tree.
Next, there is no distinction made among different types of mulch. Bark is not the same as wood chips, and coarse materials function differently than fine mulches. Bark mulches don’t absorb water like wood chips do, and fine mulches inhibit air and water movement into the soil (coarse mulches don’t cause this problem).
Finally, there is the statement that repeated application of bark will raise soil pH and increase manganese levels. There is no research I could find to support either one of these claims.
The purpose of this column was to educate – but it has failed to do so for the reasons outlined above. Where did the CRAP analysis fall apart?
We need to go back to looking at the author’s credentials. It’s not apparent from his publication record that he’s researched mulches at all. His work was primarily on composts, with the most recent article published in 1998. Nor has he published articles relevant to management of woody plants.
Urban horticulture and arboriculture are relatively new fields of study that are rapidly evolving. Information once accepted as factual decades ago may no longer hold true, as newer research changes our understanding of the way that plants and soils work in managed landscapes.
By Visiting Professors Dr. Charlie Rohwer and Ulrike Carlson
I’ve had this dream of doing a full academic etymological study of oranges, with the help of a second-cousin-by-marriage linguist and her historian husband. Being honest with myself, I know that’ll never happen. And also, honestly, they’d have to do all the work anyway.
But, the Garden Professor’s Facebook post about the citrus family tree revived my interest. Not for a full-blown academic analysis of the word ‘orange,’ but for a blog-friendly, factual, interesting post. So I got my linguist cousin Ulrike Carlson to edit for accuracy too.
The name given to the orange by Linnaeus was Citrus aurantium, and the only other citrus species he noted in his first volume of Species Plantarum was Citrus medica. The current taxonomy of citron is Citrus medica L., and bitter orange (or Seville orange, used for marmalade and Belgian beer) is Citrus aurantium L. According to Linnaeus, sweet orange and pomelo were separate varieties of C. aurantium (var. sinensis and var. grandis, respectively). For a pretty image of the family tree, see the National Geographic article here. Basically, it is now known that all common citrus fruits are hybrids derived from citron, mandarin, pomelo, and papeda.
The current taxonomy for sweet orange, Citrus sinensis (L.) Osbeck, clearly defines the fruit’s Eastern origin (sinensis comes from Latin for ‘Chinese’) and altered nomenclature (Osbeck refined Linnaeus’ original taxonomy). But the name given to bitter orange, C. aurantium, points to its South Asian origin, and here’s why. The Tamil (south India) word for orange transliterates to ārañcu; Sanskrit words look similar; the Persian nārang is derived from there. As the bitter and sweet orange hybrids were likely made somewhere between Northern India and Southern China, it would be expected that the European names for these fruits come from these or nearby areas too. The origin of Linnaeus’ aurantium are obvious. Aurantium is Latin for the orange tree, and aurancia is the fruit. If you say these words aloud, they all sound similar to each other, to nārang, and to the English orange.
But here’s where it gets more interesting, with a preface: the word apple has historically been used to describe any fruit that’s not a small berry. Also, bitter oranges were common in Europe before sweet oranges. In fact, when sweet oranges came on the scene in the 17th century, wealthy people built greenhouses or gardens (“orangeries”) specifically for the new, more delicious versions of the fruit.
Orangery at the Château_de_Versailles
By Djampa – Own work
My first time in the Netherlands, I noticed orange juice is called sinaasapelsap. I don’t know Dutch really, but…doesn’t that mean ‘Chinese apple juice?’ Sinaas: Chinese (sinensis); apel: apple; sap: …sap (juice)? I knew in French that it’s jus d’orange (juice of the orange), and I knew ‘orange’ in Spanish is naranja (looks & sounds a lot like orange and narang). Why would the Dutch call it Chinese apple juice? Fast forward a couple years, I’m in Denmark, and what do I see? Appelsinsaft. CHINESE APPLE JUICE…English, Dutch, Danish, they’re all Germanic languages. Shouldn’t the Germanic languages call it orange juice, like I do? Then it hits me. English is the odd duck here. The Germanic languages call orange juice ‘Chinese apple juice’. This reflects the name Linnaeus gave the sweet orange (var. sinensis, or ‘Chinese’). Best I can tell, among Germanic languages, only English, Afrikaans, and Scots gets their word for the sweet orange from the older word for the bitter orange, nārang.
That’s not the last word on the subject though. You can go to Italy for sweet oranges and get arance, the Czech Republic and get pomeranče (apple-orange), Ireland and get oráistí, Bulgaria and get oranzhev, or Portugal and get laranjas (aka, oranges). All words that come from nārang or aurancia. You can go to Estonia, Finland, Sweden, Norway, and Germany and get some kind of Chinese apples (aka, oranges). But even as most Italians eat arance, you’d instead ask for a partuallu in Sicily. Or you’d eat a portokáli in Greece, portokall in Albania, etc. The Portuguese, with their awesome shipping routes, imported sweet oranges from China, then grew and distributed them through Europe in the 17th century. They were a big improvement over the bitter orange (which would you rather have, marmalade from a bitter orange, or a juicy sweet orange?). So some countries called the sweet orange by the name of the proximal country they were shipped from, Portugal. Bitter oranges (AKA Seville oranges, named from where they were grown) are called pomerans (from apple-orange) in Swedish, Pomeranzen or Bitterorangen in German, pomeransen in Dutch…so it seems that when sweet oranges came to Germanic-speaking countries, the languages kept the word they’d been using for the bitter orange (calling it an orange-apple or bitter orange), and added a different word for the sweet orange, calling it a Chinese apple. This is all complicated because political boundaries have changed a lot in Europe, and languages borrow from each other. So northern Germans might still eat Chinese apples, but southern Germans might eat oranges.
Also, if you’re interested and you’ve made it this far, the color orange is so named because that’s the color of the fruit. It’s not the other way around. It’s a pretty recent color descriptor. That’s why robins, with their orange breasts, are called robin red-breast. There was no word for the color orange when the robin was first described.
Also of great interest is the House of Orange. If you’ve seen a Dutch soccer game, or been to the Netherlands, you’ll know they like the color orange. William I of Orange, basically the founder of the Netherlands, came from a principality called ‘Orange’, now in France, and the Dutch celebrate their royal family with the color of its namesake. BUT, Orange, France was named, a couple thousand years ago (before the fruit came to Europe), after a Celtic water god, Arausio. At the time, this had nothing to do with the fruit or the color. HOWEVER, since the middle ages, the crest of the French city shows orange fruit on a branch, and the crest for the German city of Oranienbaum (orange tree) has, you guessed it, an orange tree. According to Wikipedia, Oranienbaum was named after the Dutch House of Orange.
For more about how these languages are related, here’s a ‘simple’ chart.