I’ve mentioned numerous times in the past (here, here, and here) that the basis of organic growing is high-quality, healthy soil. It’s like that old saying about real estate value, i.e. “location, location, location.” Except with organic growing and having healthy plants, it’s “soil, soil, soil.” However, even with the healthiest of soils, there are many other factors in growing healthy plants.
Eliot Coleman has written that growing organically is about minimizing stresses to plants. Plants are like us, in that when our bodies are stressed too much, we get ill. We have more control over changing things though. If we get too hot or too cold, or too hungry or too thirsty, we can get up and move to eliminate those stresses. Plants are stuck where we plant them, so it’s up to us to make their conditions as stress-free as possible for them. That’s why making the soil healthy is so important, because the plants are stuck with what they have wherever they’re planted. If they get stressed, they are prone to disease, insect damage, and stunted growth. So first we need to understand what their needs are, so we can make sure to provide for those, in order to minimize stresses to the plants.
Vegetable plants stress easy. That’s because they aren’t survivors, like wild plants (including weeds). Most of the conditions that stress vegetable plants are ignored by weeds and other wild plants. And even though a lot of wild plants are edible, they just don’t have the great flavor of veggies that have been bred over decades or centuries. That’s the reason for the unwritten compact between mankind and crops, first identified by the great plant breeder Luther Burbank, viz. that we agree to breed and nurture our crops in exchange for them providing us with tasty, nutritious food. 1
A month-and-a-half ago my son Sean was back here to film some educational videos. One of the videos identified a lot of plants’ needs, and it amazed me how many of those needs can be distilled out of basic high school biology. All living things, animals and plants, undergo respiration, which for us we think of as breathing. But respiration is also a cellular metabolic event. Plants do it only at night though. During the day, they do something special that animals can’t. It’s called photosynthesis, which means using light, “photo-”, to combine chemicals, “-synthesis”, to make their own food. (Some parasitic and saprophytic plants don’t have chlorophyll and don’t photosynthesize; instead, they get their food from living (parasites) or dead organisms (saprophytes).)
Photosynthesis and respiration have nice, chemically balanced formulas or equations, but we’ll stick with plain language. During photosynthesis, plants take in water and carbon dioxide, and in the presence of sunlight convert them to glucose, which is a simple sugar, and oxygen. During that process, another complex chain of chemical reactions occurs (citric acid or Krebs cycle) which stores chemical energy in the form of ATP (adenosine triphosphate). At night, the process somewhat reverses. When there is no sunlight, the plant takes oxygen and some of its glucose and converts them back into water and carbon dioxide. That’s respiration. During that process, the chemical energy stored in ATP is released and provides the metabolic energy for growth, and flowering and fruiting. Most people don’t know that plants do their growing at night. Plants also use the minerals that the roots adsorb from the soil in their metabolic processes. For example, nitrates help make amino acids, proteins, and DNA. Potassium activates the enzymes that make all the above processes possible. And magnesium, and iron are both used in chlorophyll.
So, looking at these processes helps explain what some of plants’ needs are and why. Starting with numero uno, i.e. the soil, we see why the soil should be (1) fertile (i.e. have all the right minerals in the right amount), (2) have the right amount of tilth or looseness (so the roots use less energy to grow and also have access to oxygen), and (3) have a lot of humus (decomposed organic matter), to help facilitate fertility and tilth and provide food for micro-organisms.
All green plants need sunlight for photosynthesis. Pretty much all vegetable plants need full sun. Shade or partial shade doesn’t work well. From 10 a.m. to 4 p.m. is an absolute minimum, but all day is better.
All living things need water, including plants. They need the right amount too: the Goldilocks amount, i.e. not too much and not too little. Vegetable plants don’t like to be in standing water. Because we usually get a considerable amount of rain, and our soil is heavy, we’ve built up our planting beds into raised beds. This helps drain the soil, so it isn’t too soggy. Vegetable plants also get stressed from underwatering. By the time a plant shows signs of stress from not enough water, like wilting, it has already undergone damage. If you push your fingers into the ground, it should feel damp. A ball of soil should feel like a “wrung out” sponge.
Plants also need air (oxygen and carbon dioxide). Air seems easy, it’s everywhere. But implicit in that is that they need a certain amount of space around them. If plants are too crowded, they get stressed, whether they are planted too close together, or are crowded by weeds. Additionally weeds compete for all the other requirements besides air, like water, minerals in the soil, sunlight, and so on. Keeping weeds out of the garden is truly more important than just aesthetics. Besides space around them above ground, plants’ roots need space around them too. Whether it’s seedlings too confined in their containers or plants put in the ground too close together, all vegetable plants need adequate space in the soil.
Other conditions that create stress for plants arise from weather conditions. Optimal conditions vary from one type of vegetable to another, but those weather conditions include temperature, precipitation, and wind. Temperature can be controlled or modified at your location by protecting with cloches, cold-frames, wall-o-waters, row covers, caterpillar tunnels, high tunnels, greenhouses, and so on. If there’s inadequate precipitation, we can irrigate. Windbreaks provide relief from high winds. We can’t change the weather, but we can somewhat mitigate it through proven technologies. All of these techniques exemplify what Curtis Stone (The Urban Farmer) frequently says: “Agriculture doesn’t exist in nature.”
Lastly, I’m going to mention something that hopefully doesn’t sound too weird or controversial to you: Love your plants. Talk to them. Send them positive energy. I read once that veggie plants are essentially solar-powered sugar factories. While that’s technically true, I guess, I prefer not to think of plants or farms as some kind of food-producing factory. Plants are alive, sentient beings. When you treat them well, they reciprocate fully. The key is to learn, study, and research what plants’ need and the signals they give to communicate whether they’re being fulfilled, and thus stress-free. Stress-free plants are happy, healthy plants that provide us healthy food —-Steve.
Gardening When it Counts, by Steve Solomon, pp. 13-15.