Welcome back to another week of the Learning Garden series, where we all hold virtual hands and learn a bit about the botany and agriculture of plants that feed us, our co-evolutionary history with them, and what that could mean for the future of the human-Earth relationship.
Up this week: the Nightshade family, in all their sometimes delicious, sometimes toxic, sometimes psychoactive glory. We’ll also talk about their insect companion, the mosquitos, and how the nitrogen cycle binds each of them with us.
Familiar species of Nightshades include: tomatoes, peppers, eggplants, potatoes, petunias, and the infamous bella donna. Some members of this family also have psychotropic properties, such as tobacco and datura, or “thorn apple”.
In deep evolutionary history, members of the nightshade family saw huge species diversification as a result of mass extinction. After the asteroid, 3/4 of the Earths biodiversity went the way of the dinosaurs (literally, in this case). It was time to adapt or die, and adapt they did. While domestication of nightshade plants all originated from indigenous farmers of the Americas (except eggplant, which came from India), the nearly 2,700 plants in this family enjoy global distribution everywhere except Antarctica.
Here in Wisconsin, it’s just after labor day on the farm. For the past 4-5 weeks, we’ve been harvesting thousands of pounds of tomatoes. This is my 3rd year spending a significant amount of time with this particular crop. In that time, the other farmers and I have paid many a blood tax owed to the brood of mosquitos. That may be why the two are already linked in my head. However, tomatoes are to humans what humans are to mosquitos, in more ways that one.
Before we unpack that, let me share some hot tips about growing tomatoes organically for those who can’t get enough mouth-watering fresh tomatoes at market:
Always source organic certified seed from a reputable source. Seeds from organically grown plants are selected for natural resistance to the common diseases. Plus, they don’t contain systemic pesticides known as neonicotinoids, which carries through every cell of the plant and has been shown to have disastrous affects on honey bees and the native pollinator populations.
When starting seed, save space, heating, and potting mix by seeding tomatoes in rows in an open flat. When they reach 3” tall, pot them up into celled trays. We do size 50 cells per flat.
If you smoke tobacco, wear gloves when handling tomato plants. Tomato mosaic virus can spread through tobacco residues.
Don’t be shy about pruning, especially in the first few weeks after transplant. Simply snap off the suckers, or side-shoots, which should break away cleanly from the stem. This allows for improved airflow, easier access, and more productive fruit-bearing.
Trellis your tomatoes, and by this I mean more than a tomato cage. Most healthy tomato plants will topple and break those cages once fruit starts coming. We use a basket weave method of trellising, but there are many options out there that work depending on your scale and what you have access to.
Don’t skip fertility. More on that later. Enrich your tomato beds with pelletized chicken manure, bloodmeal, or finished compost.
HARVEST REGULARLY! This is my #1 most important gardening tip, no matter the crop. I see people invest a bunch of energy and resources into their garden in the spring, and then watch as the plants go from ready to harvest to damaged and rotting. Think of starting a garden like a college course. You can’t only include class time in your schedule (aka, setting up and planting). You also have to schedule time to do your homework (harvesting), which is usually 2-3 hours for every hour spent in class.
If you want more about growing organic tomatoes, let me know and I can put something together with more detail and photos.
For now, let’s get back to the topic of fertility. Humans, tomatoes, and mosquitos all have at least one very important thing in common, encoded in our molecules - we need nitrogen (aka protein) to successfully produce offspring.
Nitrogen is the blood that flows in our veins that mosquitos need, not necessarily to survive, but to lay eggs. It’s a little known fact that some species of mosquito are considered pollinators as they feed on the nectar of plants for energy, while blood meals are typically reserved for brooding females.
Nitrogen is returned to the soil via poop or death, which becomes compost for tomatoes. Without that dense energy source, a hard-working, heavy-producing domestic tomato plant can turn yellow, stunted, and vulnerable to disease. Tomatoes on malnourished plants are less juicy, flavorful, and numerous.
I know this to be true from my first garden back in the day. Formerly, as a vegan, I tried “veganics”, which avoids use of compost and amendments based on manure. After a single season, it was clear to me that trying to grow vegetables without any inputs from animals was like trying to increase productivity in a workforce without raising wages. My tomatoes went on strike, and the next year, I incorporated composted goat manure. Just like that, I struck tomato gold.
In our bodies, nitrogen reaches a gestating parent through protein-rich food, such as meat, fish, legumes, seeds and nuts, dairy, and mushrooms. From my experience as a birthing mother, it’s safe to say that one’s relationship to protein changes when you’re growing a human inside your body. Cravings are like commands. If you’ve made out okay on a low-protein vegetarian or vegan diet before getting pregnant, you may be in for a rude awakening about the nutrient cost of procreation. This is an open invitation to anyone in that position who wants support in incorporating meat back into the diet - I’ve been there, and I’m here if you want to talk.
So what happens to the nitrogen cycle in a functioning ecosystem? It circulates. It goes from soil/air, to plant/mushroom, to animal, to water, to atmosphere, and back. In fact, the Earth’s atmosphere is the largest source of nitrogen, but most of that isn’t usable by lifeforms on Earth. Through nitrogen-fixing plants, like legumes, and their bacterial partners in the soil, atmospheric nitrogen is brought down into the soil in usable forms. Lightening from thunderstorms also has an effect on converting atmospheric nitrogen.
What happens, then, when one majorly prevalent species removes itself from the nitrogen cycle? In most modern people’s lives in America, we are interrupting the flow of usable forms of nitrogen we naturally produce. Our poop, for example, does not enter the ecosystem much. It goes to a wastewater treatment plant, or a septic tank, before it gets filtered out. Then it’s either sent to the landfill, incinerated into the atmosphere, or sometimes it gets processed into biofuel or fertilizer. The vast majority of it, however, goes up in smoke.
The other major source of nitrogen we leave behind is in the form of our bodies. If you read my previous post on green burials, you already know how the funeral industry has successfully sold most Americans on burial methods that give nothing of value back to the land after death.
With all that in mind, let’s take off our human-goggles for one moment and set aside the fact that mosquitos are irritating as hell. We don’t have to forgive them for being the world’s most deadly animal (even more so than humans ourselves).
If we zoom out, from the perspective of the nitrogen cycle, they’re kind of like little Robin Hoods. They take the nitrogen we’re hoarding from our bodies, in the form of blood, and put it back in ecological rotation, even against our greatest efforts to thwart them. They’re insurgents, risking life and limb to get a drop of blood from our juicy stash and flit off to the nearest pond or puddle.
From there, eggs are laid, and larva hatch. Those larva feed an impressive number of animals, each carrying with them the nitrogen molecules sourced from your blood: tadpoles, fish, turtles, dragonflies, and other aquatic insects. The larva that make it to adulthood are fed on by bats, hummingbirds, spiders, and other birds.
While mosquitos were present on Earth long before our most ancient hominid ancestors, they took a special interest in us once we arrived. Many species alive today have evolved since dinosaur times to specialize in feeding on human blood. They’ve adapted to bite us through our clothing. They’ve developed tolerances to the pesticides in our bug spray, both what we spray on ourselves and in the environment. They’ve developed a special taste for people with type 0 blood. They are attracted to the colors red and orange, like, say, tomatoes and peppers. They also prefer a pregnant person’s blood. And they aren’t going anywhere, any time soon.
An honorable mention for insect companion for nightshades, although it’s more of an ectoparasite than companion: Tomato hornworm. You’ve seen these caterpillars, lime green that start out small and get almost as big as a hot dog:
To be honest, even though tomatoes are one of our most labor-intensive and costly crops, I can’t hold much ire for these caterpillars. Once I found out what they mature into, it took my breath away. I remove them from the plants, of course, but it feels more like harvesting a tasty chicken treat than killing for sport (like I do with mosquitos).
If you’re looking for solutions for hornworm, I don’t have much other than check your plants multiple times a week. The only organic-certifiable solutions like BT (Bacillus thuringiensis) don’t make much sense for most people at a garden-scale of production.
For mosquito infestations, I can’t recommend much either. The best I can offer is to suit up in a beekeeper’s jacket, long pants and boots, spray something if it makes you feel better, and shower immediately after being outside and getting a bunch of bites. It seems to take the itch down a notch.
There is always the passage of time. At the very least, those of us in Wisconsin and the upper Midwest can see a remission of mosquitos at the change of the season. We woke up this morning, after temps dropped below 50 overnight, and found the air outside to be almost mosquito-free. A vast reduction from the day before!
Even so, plenty of farmers reach a breaking point in a post-flood mosquito swarm like we have just experienced, and I get it. There are times when, if I had another viable option, I might have chosen to quit.
However, for now, I take solace in the solanaceous vegetables that we grew. The rich red flesh of the tomatoes, sweet crisp rind of a pepper, the spice of chiles, the creaminess of the eggplants. As for my family and me, we’ll continue paying the blood tax in exchange for rich flavor and full bellies.
Thanks for joining me on this Learning Garden journey, and if you made it this far, please like/follow/comment/share.
<3Roxoxoxo
Sources (if not already linked):
https://www.britannica.com/plant/nightshade
https://blog.nwf.org/2020/08/meet-the-squad-of-mosquito-eating-species/
https://www.nrdc.org/stories/neonicotinoids-101-effects-humans-and-bees#regulations
https://extension.illinois.edu/blogs/garden-scoop/2020-07-25-history-tomatoes-how-tropical-became-global-crop
https://pmc.ncbi.nlm.nih.gov/articles/PMC3682748/
https://alevelbiology.co.uk/notes/nitrogen-cycle/
Great read! Has me reminiscing about a particular gardening season when tomato horn worm showed up on my plants, quickly followed by Polistes erythrocephalus, a parasitic wasp that covers the caterpillars in cocoons. The baby wasps emerge and eat thru the caterpillars, leaving a deflated balloon-like corpse. No idea if either of these species are native. And I also never caught a glimpse of the adult wasps themselves! Have you seen those guys?