The “safe seed pledge” is meaningless

The seed catalogs have started showing up in the mail, and a great number of them include something like this on the first few pages:

safeseed

Here’s the thing: NO ONE is selling genetically engineered seeds to home gardeners. There is one company, funded by kickstarter, that is trying to sell genetically engineered seeds of a glow-in-the-dark plant sometime in the future (though, like a lot of kickstarter project, the actual release date keeps getting delayed) but other than that, genetically engineered varieties are only being sold to commercial farmers, and only after the farmer has signed a pretty comprehensive licensing agreement.

You can go to the store and buy food made from genetically engineered varieties — essentially anything that contains corn and isn’t labeled as organic will be — and you can stop by the pet store and pick yourself up a fish with jellyfish genes, but no one is trying to sell you genetically engineered seeds.

So those pledges in seed catalogs promising they contain no GMO seeds are technically true, but also pretty meaningless. So if you are worried about accidentally getting a GMO variety, don’t be. And if you wish you COULD grow one, sorry, you are out of luck, unless that kickstarter project ever actually gets up and running.

— Joseph Tychonievich

Cold Stratification for seeds

You may think of spring as the time for seed sowing, but I do a lot of seed planting now, in the fall. The reason is that most of the cold hardy perennials, trees and shrubs that I like to grow produce seeds that require cold stratification.
This simply means that they require a period exposed to cold temperatures while the seeds are moist and hydrated before they will germinate.

The requirement for cold is a pretty straight-forward adaptation to life in cold climates. Seeds that ripen in the summer and fall might not have time to get established before winter if they germinated right away. The requirement for cold means the seeds don’t actually sprout until spring, giving them a full growing season to get ready for the next winter.

seedbed
An outdoor seed bed is an easy way to stratify seeds

You can — and I used to — give seeds this cold period in the refrigerator. Three months in the fridge in a plastic bag with a damp paper towel to keep the seeds moist is long enough for most everything, though the exact period of cold required varies by the plant. The fridge works, but I think it is way easier to just do it outside. So the past few days I’ve been busy sowing seeds out in my outdoor seed beds. They’re just raised beds, filled with potting media, and covered with a screen lid to limit the number of weed seeds that blow in and keep disruptive animals out. I plant my seeds in the fall. Come spring, after the seeds have had their dose of cold, they sprout.

Dianthus seedlings ready for transplanting
Dianthus seedlings ready for transplanting

Once the seedlings have grown on a while, I dig them out, separate the individual plants, and put them out into their final locations in the garden.

Individual seedlings separated and ready for planting
Individual seedlings separated and ready for planting

I do this with more and more seeds every year, even for perennials that don’t require a cold period to germinate, simply because it is so easy. No fussing around with lights or checking the calendar or even much watering. Just plunk the seeds in, and dig out the plants once they are big enough.

Microclimate follow-up

Last year I talked about using cheap min-max thermometers to get a handle on the specifics of the micro climates in my garden, and I was reminded recently that I never followed up on what I actually found out, so that’s what I’m doing today.

Remember that these results are just ONE data point, specific information about conditions in my particular garden. Your conditions will probably be different, so don’t try and extrapolate from these to your garden. Instead, if you are curious about your micro-climates, get a few thermometers, scatter them around, and see what happens.

20141104_130607

What I did:

I placed thermometers three different locations – up in the air on the north side of a shed, on the ground out in the middle of an open area, and on the ground up against the south side of a shed. I expected the ground thermometers to be warmer, thanks to the insulation of snow, and the one on the south side of a shed to be warmer still, thanks to the added heat from the sun.

What I found

I was surprised on several fronts. First, the south side of the building was, for me, only warmer during the day. I recorded higher high temperatures, but at night, it dropped down exactly as cold as everywhere else. This may be partly because we have extremely cloudy winters here in Michigan, so there isn’t a whole lot of sun to warm up the south side of anything. The wall is also an unheated shed, so there was no extra heat leaking out from inside the way there would be up against the walls of a house, particularly if it is old and poorly insulated.

Ground level, under the snow, was as I expect warmer than the air temperature above. Much warmer than I had expected, in fact. We had about a foot or so of snow during the coldest part of the winter, and that snow kept thing more than 20 degrees F (~11 degrees C) warmer than the air temperature above the snow line. Keep in mind that the USDA hardiness zones are based on 10 degree F differences, so that thick layer of snow kept things almost two zones warmer. I knew snow was a good insulator, but I didn’t realize it would make that big a difference. Thank you Lake Michigan for all the frozen white stuff!

What I’m doing with the information:

I’m no longer trying to put tender plants against the south wall – Instead, I’m piling on a layer of mulch after the ground freezes to augment the insulating power of the snow. And given that south facing wall is much warmer during the day, I’m using it to grow heat loving plants that tend to pout in my cool, Michigan summers. Melons, peppers, and eggplant all adore the extra 5-10 degrees F (~2-5 degrees C) that south wall adds to my daily high temperatures.

Easy Overwintering

I love growing tender plants as annuals over the summer. But I don’t like buying them again every year, so I try to overwinter as many as I can indoors once frost threatens. However, I have pretty limited windowsill space, so I can’t keep many plants in active growth all winter. Luckily, I’ve found a simple hack that works for a surprising number of plants.begoniaoverwintering

The above begonia is on a high dark shelf. It will sit there all winter, getting essentially no light, and I won’t water it. All those leaves will drop off, leaving nothing but dead looking stems. But come spring, when I put it back outside and water it again, new leaves will start growing and it will come right back.

Quite a lot of tender plants can do this. Just keep them dry, preferably on the cool side (unheated basements are perfect), and they’ll go dormant, usually dropping their leaves, and wait patiently for spring. I personally have done this with both cane begonias (as pictured) and the rhizomatous rex begonias, pelargoniums (the annual “geraniums”), and lots of succulent plants like agaves and cacti. I’ve seen first-hand other people using the same method with great success with brugmansia, bananas, and tender shrubby hibiscus. It seems like it is works most often with plants with thick, woody or succulent stems, but I keep trying it with new things and being surprised when they come through just fine. So if you’ve got some cool tender plant you’d love to over winter, but no window space left, shove it in the basement and see what happens. If it comes back fine in the spring, please comment on this post so the rest of us can learn from your experience!

— Joseph Tychonievich

Add one species, get four new ones

Here’s an interesting twist on the whole native, non-native discussion… sometimes the introduction of new species of plants can trigger the evolution of new species of insects! Sometimes, in fact, a whole bunch of them, as is described in the coolest new research paper I’ve read in ages (Actual paper, behind a pay wall) (A brief Summary)

Introduce apples, trigger the evolution of four new species of insect
Introduce apples, trigger the evolution of four new species of insect

Basically, there is a fruit fly, Rhagoletis pomonella, native to Eastern North America that lays its eggs on the ripe fruits of native hawthorns. It is part of a whole group of species of flies that each go after a different kind of fruit – blueberries, snowberries and dogwoods each have their own species of closely related fly. When Europeans arrived and introduced non-native apple trees, the hawthorn fly started laying eggs on the apples as well, and got the name of apple maggot. But here’s the crazy bit: The hawthorn flies didn’t just expand their diet, they actually evolved to a new race, a new species in the making, that live exclusively on apples.

These flies have very brief life spans, so the adults must emerge at exactly the right time or there won’t be ripe fruit to lay their eggs on. But apples and hawthorns ripen nearly a month apart, so the apple targeting flies have evolved to emerge several weeks earlier than the original hawthorn flies. In addition to diverging in time of emergence, the two types of flies have changed their preferences in smells. The original fly is attracted to the smell of hawthorns, and avoids the smell of apples, while the new flies show the exact opposite behavior, each homing in on their target host, be it new or old.

The final piece of these two types of flies becoming two different species is that they each now mate only on the fruit of their tree of choice. This is important, because now the apple and hawthorn flies don’t interbreed due to their preference of mating location, and being a reproductively isolated group is the most commonly accepted definition of a species. Now the two types of flies will continue to diverge, as the lack of interbreeding means more and more genetic differences between the two populations will build up over time.
All of this is very cool, and has been long understood. Here’s the EVEN COOLER part from this new research: The divergence of one kind of fruit fly into two is cascading through the ecosystem. There are three species of parasitioid wasps that lay their eggs on the hawthorn fruit fly that have diverge into new forms that specialize in the new apple fruit fly. Just like the fruit flies, the timing of their life cycle, their preference and avoidance of the smell of the ripe fruit, and their mating habits have shifted to create different apple and hawthorn specific races. So where there was one fruit fly and three wasps, the introduction of the European apple has lead to the evolution of one additional fruit fly, and three new wasps.

I’m not sure what import this has, if any, in the ever raging native-versus-exotic debate in horticulture, but it sure is cool – the evolution of new species happening right before our eyes.

Joseph Tychonievich

Cactus grafting fun

I’ve been grafting cactus this summer, and made this:

grafted cactus

It is a seedling of the gorgeous hardy cactus Echinocereus reichenbachii, grafted onto Pereskiopsis spathulata, an odd, leafy cactus I wrote about earlier.

Why do this? Other than the fact that it is darn cool? Well, because that vigorous, fast growing rootstock pumps a lot of energy into the cactus grafted on top, making the grafted cactus grow a LOT faster than left on its own roots.

grafted cactus startThis is a (terrible, blurry) picture what the graft looked like when I first made it back in July. Just three months later it has grown to enormously, while the seedlings I left on their own roots look pretty much the same. I’ll let it grow on the graft for a while, then probably next year some time, cut it off, and move it into the garden, getting me to a reasonably sized plant in a reasonable amount of time.

So… if you want to speed up the growth of a pokey cactus, try grafting it. The process is crazy easy, lots of fun, and very thoroughly explained here.

 

“Lazy” corn and gravitropism

Inspired by Linda’s post about thigmomorphogenesis, I decided today I would add the word gravitropism to your vocabulary. It simply means growth in response to gravity. Shoots of plants grow up, because they are negatively gravitropic, they grow against the pull of gravity, while roots are positively gravitropic and grow down towards the pull of gravity.

And why is that so important? Well… this is what happens when gravitropism is missing.

cornlazyplant

To the left is normal old corn. The plant to the right was not sat on by a raccoon or anything, it simply has a mutation in a gene called lazy plant1. I’m not kidding. That’s the official, scientific name for this gene. Geneticists have fun with their names, though fruit fly geneticists are for sure the kings of silly gene names. This gene got that name because, as you can see, without a functioning copy of that gene, the corn plant no longer can detect the pull of gravity and so flops down in a “lazy” manner.

This corn is just odd, of course, with no real value (though it was fun to grow) but similar mutations are what give us some of the “weeping” or trailing forms of popular ornamental trees and shrubs.

Bad power line pruning

Driving home today, I saw this lovely sight:

powerlinepruningOur local utility company has been busy butchering trees around the power lines.

Every plant person I know complains about this, but I honestly don’t think there is much hope for a change. Power companies don’t want limbs falling on the electric cables during storms, and they’re not likely to start spending money to hire real arborists to do the pruning.

What I really wish is that people would start thinking a little more before putting in a tall tree directly under electric lines. I’m sure these went in as cute little babies, I know it can be hard to visualize what a small tree will grow into, but we do really need to do a better job of it. If you are looking to plant, take the time to look up the tree in question and see how fast it is going to grow. Google will usually tell you, and if you are planing conifers, the American Conifer Society has an amazing website which will tell you the growth rates in inches per year of just about any conifer you can imagine. Check it out, and do the math, and see just how fast that little spruce is going to be causing problems before you start digging holes.

Why doesn’t my plant look like it did last year?

I get versions of this question often. You have something in the garden, but this year it looks a bit different than it did before. There are a bunch of different things that could have happened to cause this change, and I’ll attempt here to make a complete list of them.

Rootstock

Trees and shrubs, including things like tree peonies and roses, are often grafted, so the part with the pretty flowers or delicious fruit is stuck onto the roots of a different variety, often not as pretty/useful/tasty but more vigorous and/or easier to propagate. Sometimes shoots come up from that rootstock and take over the plant. The best sign will be to see if the shoots that look different are coming up from the very base of the plant. Cut all the shoots with the off-type flowers or fruits as completely as possible to allow the desirable parts of the plant to continue on.

Reversion

This is most common with variegated plants that are chimeras, though there are a few chimeral varieties which have multicolored flowers rather than multicolored leaves. I wrote about what a chimera is here, but the short story is: Many variegated plants are made up of two different cell types living together. If one cell type starts taking over, you loose the bi-colored effect of the variegation. As soon as you notice them, cut out the reverted shoots to keep them from out growing the multicolored parts.

A variegated sport on a lilac
A variegated sport on a lilac

Sports

Sports are chance mutations, and sometimes a flower will just up and change color. Usually, a sport will only change one aspect of a plant, most often color, while size and shape and everything else stays the same. New variegated varieties almost always come into being as sports. Sports will almost always be isolated to just once branch or section of the plant while the rest of the plant maintains the original color. If you like the sport, you might want to try taking cuttings. If it is an attractive sport of a popular plant, it might even be valuable.

Seedlings

Sometimes it isn’t that the original plant changed, but rather that it had some babies, and the babies look different. Confirmed self-sowers like phlox and aquilegia are notorious for this. You get a nice variety, but in a couple years, it has died out and replaced by a few seedlings which usually aren’t as nice. To prevent this, dead head after flowers fade to prevent seeds from developing.

Soil

Hydrangeas famously will change flower color depending on the pH of the soil in which they are grown. However, this is rather an anomaly, and soil conditions have no impact on the look of flowers for the vast majority of plants.

Climate

Some flowers will change their look, sometimes radically, depending on climatic conditions, often getting darker or lighter depending on temperature and the amount of sunshine. So if a plant looks different in a year when it has been unusually hot or cold or cloudy or sunny, it will probably go back to the normal coloration once your weather returns to normal.

Nursery conditions

Often plants you get at the nursery will look quite different once they’ve spent some time in your garden. Many plants from the nursery will have been treated with chemicals called plant growth regulators which are used to keep the plants short and compact. As those compounds wear off, the plants will grow taller and looser. Also, commercial greenhouses are usually warmer than your garden and often exclude UV light which can chance the coloration of a lot of flowers.

Contamination

If your neighbor gave you a clump of their favorite old bearded iris, but after a couple years the iris they gave you is replaced by a different color or a different plant altogether, they likely accidentally included a bit a different, more vigorous plant along with the one they gave you. Your best option here is to lift up the whole clump, wash all the soil off the roots so you can see exactly where one plant ends and the other starts, and just replant the ones that are true to type.

irisglyphosate
A whiff of glyphosate caused this iris flower to bleach out.

Herbicide drift

If you are spraying something like glyphosate (active ingredient in roundup) sometimes a bit of it can drift onto plants, not enough to kill them, but enough to cause them to be deformed or discolored. Glyphosate drift in particular will often cause flowers to be bleached out, white or nearly white. In this case, just be more careful next year, and everything should return to normal.

Forgetfulness

Okay, let’s just admit it. We don’t always remember that we moved something or what we bought or exactly what a new plant looked like last year. Sometimes there is no great scientific mystery beyond the fact that we’re all busy and don’t keep as good records as we know we should.

Joseph Tychonievich

Thoughts on reproducibility and reliability in science

You’ve probably heard about a project that attempted the replicate 98 psychological studies and found that only a third of them were reproducible, the other two thirds produced different results – sometimes very different, more often only somewhat so.

Though psychology was the subject of this study, you shouldn’t assume the results were unique to that particular field. The are plenty of reports of similar failings and the so-called ‘Decline effect’ in other scientific disciplines.

So why is that? There are a lot of reasons. Research can be poorly designed, based on flawed assumptions, and sometimes an unlucky flukes can create false positives. It is also the sad fact that science is done by humans, and humans are complex things with a lot of motives besides the pure quest of knowledge.

I think the general public often fears that scientists are swayed by money from corporations and/or special interest groups, but my experience in academia is quite different. I’ve never heard anyone concerned they might loose a corporate grant. I have heard lots of people, more-or-less continuously, worrying that if their experiment doesn’t work out they won’t be able to get their PhD, land a job, or get tenure. There is enormous pressure to find something significant, to find an effect, and it matters not at all the political ramifications of that effect. So if you are worried about Monsanto buying off scientists to say GMO are safe to eat, don’t be. Convincing data that GMOs are somehow unsafe to eat would be of enormous significance, completely rewriting what we know about genetics, and would come with huge professional rewards. In my opinion, you should be more concerned that some new study showing that X, Y or Z makes plants grow bigger or yield more is actually the result of fervent, wishful thinking on the part of a grad student desperate for publishable data.

So what’s the solution? There has been a lot of talk in the academic community about making it possible to publish negative results and provide funding to regularly attempt to replicate previous studies. I hope these changes go into effect, as they could make an enormous improvement in the reliability of new findings.

In the mean time, you, as a concerned gardener, should take information supported by only a single, isolated study with a big grain of salt, particularly if it seems to contradict findings from other research. If you go to scholar.google.com and start searching around, make sure you read as much of the research on the topic as you can, so you can differentiate between the intriguing new research that may well be proved wrong and reliable findings that have been sustained by several independent researchers. And always remember that while the scientific process is far from perfect, it is still the best we’ve got.