Month: February 2024

The Times They Are A-Changin’—What the new La Niña Watch means for the NH growing season

In this blog I’ve talked several times about El Niño and La Niña and how they affect climate across the Northern Hemisphere as well as their impacts on the rest of the world. We are currently in a strong El Niño with sea surface temperatures in the Eastern Pacific Ocean (EPO) that are much warmer than the long-term average. But underneath the surface the ocean currents are starting to change and the El Niño is expected to swing quickly into the opposite phase, La Niña. That will affect us in North America but also other parts of the world since both El Niño and La Niña are linked to global atmospheric patterns. Since a La Niña Watch was just issued by NOAA this week I will be talking about the changes we can expect to see over the next few months and how those changes will affect gardens and gardeners.

Daffodil crop ready, Andrew Wood , Commons Wikimedia

Review—What are El Niño and La Niña?

El Niño and La Niña are opposite phases of a large-scale atmosphere/ocean pattern that is driven by temperatures in the EPO. The pattern affects climate in many places around the globe. It is the biggest driver of seasonal climate in the Southeast and Pacific Northwest as well as in some other countries, especially in Northern Hemisphere (NH) winter when it is usually the strongest.

In September 2023 I discussed the likely impacts of the El Niño that was growing at that time and how it would affect your winter gardens. The conditions I expected have mostly been observed, although there are some local differences that are not surprising considering that each event is unique. Northern states have been incredibly warm with little snow, while in the Southeast we have had a lot of rain and cooler (although not frigid) temperatures due to wet soils and a lot of clouds blocking the sun. California is getting hit by one atmospheric river event after another, so they are also very wet and are even seeing a lake in Death Valley. I imagine they will have quite a bloom of spring flowers when it gets warmer because of the ample moisture. What have you experienced in your area? Did my earlier column get it right?

Alnarp (Sweden)—Spring Leaves, Susanne Nilsson, Commons Wikimedia

How is this season different than a typical El Niño winter?

Even though we have had the swings of El Niño and La Niña (collectively called El Nino Southern Oscillation or ENSO) for thousands of years as evidenced by layers in ice sheets in Peru and ocean sediments, there are other changes that are not cyclical. The rise in global temperature over time is showing up as a warming trend in all seasons but especially in winter. That does not mean we don’t see other swings in climate over time because ENSO and other atmospheric cycles are still occurring, but they are superimposed on the slowly rising temperature associated with increases in greenhouse gases so the cold outbreaks aren’t quite as severe and the warm spells last longer.

Sea surface temperature departure from normal for 2024-2-12.

This year one of the most notable things we are seeing in global climate is the unbelievable warmth in the Atlantic Ocean. Temperatures there now are at values consistent with June or July temperatures! This is the energy that will feed tropical storms later in summer (more on that in a minute). Scientists are still not sure of all of the factors that are contributing to these record-setting conditions, but they may include the eruption of Hunga Tonga, the elimination of sulfur emissions from modern cargo ships, and changes in the global ocean circulation.

Plum blossoms starting to bloom, John Morgan, Commons Wikimedia.

In addition, in spite of one cold big outbreak this winter across the eastern United States, most areas have been warmer than normal resulting in an early spring that has brought honeysuckle leaves to my yard more than a week early. You can follow the “green wave” north and see when it gets to your area or verify that it’s already there at the National Phenology Network site. I am concerned about the possibility of having another late frost like 2023 that could impact the peach and blueberry growers in the Southeast since our average last spring frost date is early to mid-March for most of the commercial peach region. There has been enough cold weather for most of the fruit-producing plants to have reached their required number of chill hours, which means the warm weather is making them ready to bloom. While I don’t see another cold outbreak on the horizon for the next few weeks, we have had frosts in the Southeast into April before so we are not out of the woods yet.

ENSO probabilities for 2024 as of mid-February.

When will La Niña begin?

Climatologists predict that El Niño will weaken through spring and we will swing back into neutral conditions by the April through June period. From there most models predict we will move into a La Niña by the June through August period. By NH fall (September through November) there is a 77% chance we will be in La Niña conditions. This has implications for the summer and especially for the Atlantic tropical season since in neutral and La Niña years the number of tropical storms that occur in the Gulf and Atlantic is higher than in El Niño years. Last year despite El Niño we had 20 named storms, much more than the average of 14 events. This was in part due to the unusually warm water. Most of those stayed over the Atlantic Ocean rather than make landfall due to the presence of a strong jet stream high in the atmosphere which disrupted the development of storms farther to the west and prevented a lot of damage to us in the United States. In spite of that, we still had Hurricane Idalia and Tropical Storm Ophelia, both of which caused a lot of damage to infrastructure and agriculture.

With La Niña fully in place by fall, there will be little to stop the development of tropical storms in the Gulf and Atlantic Ocean except for Saharan dust and unfavorable weather patterns in the United States that could at least shunt any storms away from land. Some early unofficial predictions are for 25 or more named storms to occur this year, although the official predictions are still a few weeks away.

Next winter, we can expect La Niña to control a lot of our climate. That means warmer and drier conditions across the southern part of the United States while cold and wet conditions return to the northern states. Here in the Southeast, that means soil could be pretty dry in spring 2025 leading to issues with planting although it will be easier to drive heavy equipment into the fields than I expect will happen this year.

Field with daffodils, Txllxt TxllxT , Commons Wikimedia

What does all of this mean for gardeners in the United States?

Because of the recent warm conditions associated with rising temperatures and enhanced by El Niño in northern parts of the country, spring is coming early to many places. That can be a good thing if you like flowers and don’t like snow, but it does mean that your early flowers will still be susceptible to frost damage if we get another cold outbreak later in March or even into April or May for northern states. So you will need to be prepared to protect the tender plants if a frost or freeze occurs.

The end of El Niño and the eventual rise of La Niña also has implications for areas that are affected by tropical systems. This includes the Gulf and East Coasts and areas downwind of those locations but can also include parts of California and the Southwest which can see impacts from tropical systems in the EPO west of Mexico. Rainfall could be hit or miss in the late summer depending on where the storms go. You should prepare well in advance of June 1, the official start of the season, because the warm ocean water could allow tropical storms to develop in May ahead of the “official” start. That means making sure you remove damaged limbs or other objects that could become wind-borne debris, make sure you have adequate drainage for heavy rain, and keep an inventory of your belongings that could be washed or blown away in a storm. Have a family plan to keep in touch and evacuate if you need to, including pets and livestock. You can find a lot of good information on preparing for and recovering from natural disasters in this University of Georgia handbook, even if you are not in Georgia or the Southeast.

Forsythia in snow, Famartin , Commons Wikimedia

While the current warm weather makes gardeners eager to get out in their plots and get started, it’s probably too early to start in most of the country except the most southern areas. But you can dream and start planning for the warmer weather soon to come!

Unpacking a Peck of Purple Genetically Engineered Tomatoes

Excitement spread across social media recently with the announcement that a genetically engineered tomato, creatively named “The Purple Tomato” is now available for home gardeners. Gardeners, plant scientists, and others rejoiced at the news that a purple tomato engineered with genes from a snapdragon to boost the plant pigment anthocyanin is now available for home gardeners to purchase. But why were people so excited? And what does this mean?

The Purple Tomato: What is it and why is it exciting and important?

The Purple Tomato was developed by a company called Norfolk Healthy Produce. The company was founded by Professor Cathie Martin (and other scientists) who is a professor at the University of East Anglia and a group leader at the John Innes Centre in the UK. On February 6, 2024 they announced that seeds were available to home gardeners in the US after clearing regulatory approval hurdles by the USDA, EPA, and FDA to assure that it is safe for human consumption, for growth in US without safety containment measures, and that it does meet its claims of added nutrients. Read more about the US regulatory process here.

For all the tomato aficionados out there, The Purple Tomato is an indeterminate cherry tomato. Indeterminate means that the plant doesn’t stop growing as long as it is healthy and will produce a “vine” that needs to be staked or trellised off the ground. Production of fruits continues throughout the season starting at the bottom of the plant and going up as long as it is healthy.  Of course, it is a cherry tomato so you’ll have hundreds or thousands of tiny fruits to pick through the season. Some gardeners love growing cherry tomatoes. Others hate it for that fact. So you win some, you lose some.

Read more on indeterminate vs. determinate here.

The tomato contains two genes from snapdragon flowers that boost anthocyanin production in the tomatoes. Anthocyanins are the plant pigments responsible for blue and blue-purple colors in plants. And they are shared across all plants with these blue and blue-purple colors, so the addition of purple pigments from a flower isn’t too out of the ordinary since tomatoes already contain similar pigments. (The reddish violet/crimson color of plants in the Amaranthaceae family (beets, amaranth, chard) are from betalin pigments, not anthocyanins, FYI.) Most plant pigments actually have the added bonus of also being highly beneficial for human health as most of them are antioxidants and have other health benefits. The incorporation of anthocyanins boost the nutrient quality of tomato since anthocyanins are considered strong antioxidants. Studies also implicate anthocyanins in reducing blood pressure and heart disease, preventing neurological disease, and slowing cancer growth due to the reduction of free radicals that can damage DNA.

Source: Overview of Plant Pigments, Springer

Now, anthocyanins in tomatoes are not new. Many hybrid and heirloom varieties of tomatoes contain anthocyanins. The tomatoes that already contain anthocyanins are the tomatoes that are often considered “purple” or “black” by seed companies and home gardeners. Like ‘Cherokee Purple’, ‘Black Beauty’, and ‘Black Krim’. However, the anthocyanins in these tomatoes are generally found in low quantities as they are only found in the skin and or the flesh just under the skin. What makes “The Purple Tomato” novel is that it is the only tomato that has the anthocyanin pigment in both the skin and throughout the tomato. Seeing pictures of the tomato, the vibrant purple color goes through the entire tomato and is striking. (It also doesn’t hurt that purple is my favorite color). Due to this purple color throughout the tomato, the fruits have a much higher concentration of anthocyanins than existing cultivars.

Another thing that excites me about The Purple Tomato is that the company claims that is an inbred/open pollinated variety. Meaning that home gardeners can save the seeds from year to year and the anthocyanin traits will continue to be present. This also signals a departure from normal genetically engineered seeds where the traits aren’t as persistent and seed saving isn’t allowed. The company does have some terms and conditions about not selling seeds (from the ones you buy or likely from any you save) and not using them to breed other varieties. But gardeners are free to save seeds and share fruits, plants, and seeds with your local community.

“GMOs” and home gardening

Despite what many people may think, until the release of this tomato there really weren’t any genetically engineered plants available to home gardeners. This marks the first time that a plant has received approval from the US government agencies that control the release of genetically engineered plant for sales directly to home gardeners. Most of the genetically engineered plants have been developed for and are available only to commodity crop (corn, soy, cotton, etc.) and select horticultural crop (papaya, some select squashes, and now Arctic apple) farmers. There’s a highly regulated process and contract procedure for farmers to obtain the seeds or plants that just isn’t practical or cost-effective for the plant developers to market to or make seeds for home gardeners.

Source: UC Davis Biotechnology Program

We’ve written several times about how, until now, there really hasn’t been genetically engineered seeds available to home gardeners, despite what some seed companies would have you believe (here and here). There has unfortunately been a lot of confusion for home gardeners thanks to misguided and/or deceptive marketing practices by certain (heirloom) seed companies that labeled their “Non-GMO certified” seeds and preached about the dangers of genetic engineering to sell more of their seeds even though there have not (until now) been any “GMO” seeds available for companies to even sell to home gardeners. Unfortunately that deceptive marketing created enough fear and fervor that most seed companies had to start labeling their seeds “Non-GMO” just to preserve their sales and cut down on harassment from folks on social media trying to “call them out” for selling GMO seeds.

Not until the release of “The Purple Tomato” has there been a home garden seed that could be labeled “GMO” and warrant companies needing to label something as non-GMO. But still it is only one plant, so is it really necessary? Or is it just a marketing tactic?

Purple Tomato Reception

In cruising through the comment section on articles discussing the new tomato, I’ve been pleasantly surprised to see the positive response that it is receiving from the public. There are lots of comments excited about the prospect of a nutrient-dense genetically engineered crop, lots of excitement about buying the seed, and even excitement about the super purple color of the tomato. The few negative comments about GMOs being “bad” have gotten a lot of pushback. I don’t think this would have happened 5 or 10 years ago.

Of course, some of the pushback is a little misguided. Statements like “all plants are GMO” show a similar lack of understanding of what is actually happening, even though it is offered in good faith. Yes, humanity has guided and shaped the genetics of all of the plants we eat over the centuries and many plants have therefore been “genetically modified” by humans. But genetic engineering is a more rigorous and scientific process. This is also one of the reasons why scientists and government agencies prefer the term “genetically engineered” or “bioengineered” to GMO or genetically modified to clear up confusion.

It does seem like the tide has shifted on public acceptance of genetic engineering where until recently many people viewed the technology with skepticism and fear, thanks mainly to misunderstanding and marketing.

Much of the fear and distrust of genetically engineered plants have been around the addition of genes to make crops resistant to certain herbicides, to produce natural immunity to insects, and other traits to increase yields. Many have wrongly assumed or claimed that this has resulted in increased application of herbicides. While application of some herbicides like glyphosate has increased, it has been at the reduction of much more dangerous herbicides. These crops have often been developed and controlled by large chemical companies that, perhaps not totally incorrectly, the general public distrusts. Plus, unintended consequences like herbicide resistant weeds have caused issues.

But the new Purple Tomato goes beyond this and I think is applauded for many reasons. One – it was made solely to boost nutrition. While there have been previous (mostly unsuccessful) efforts to do this in crops (see the story of Golden Rice), this is really the first time it has been aimed at home gardeners. Two – it isn’t one of those “big scary corporations” doing it. It is a company started by academics to promote plant science and health. Three – while the plants are patented, there aren’t strict and secretive agreements against seed saving and sharing. And four – the express purpose of the plant is to increase the healthy qualities of the plant.

In conclusion

It seems like many people are excited about this new genetically engineered tomato on the market. I know that I am. It seems like the public at large is accepting and excited by this new health-boosted tomato and the technology used to make it.

I know I’ve ordered my seeds, and many others have as well. The seeds aren’t cheap, $20 for 10, but the process to make them isn’t cheap either. I’m looking forward to trying them out in my own garden.

Disclaimer: No payment or reward was received for this article promoting the Purple Tomato and I have no affiliation with the company. Norfolk Healthy Produce didn’t even know it was being written. They probably don’t even know who the Garden Professors are and they definitely don’t know who I am. That being said, if they want to reach out with some free seeds or swag, I wouldn’t be mad at them.