Module 9: Water is Life
How to catch, conserve, and use water effectively.
Understand the cycle
After reading several of these modules you might start to notice how the lessons start repeating themselves. Add organic matter. Use mulch. Keep soil covered. Plant perennials and natives. Cultivate a diversity of plants. Yep, I say those things often and that's by design. Because growing a food forest, unlike a "conventional" garden with rows of all the same plants and bare soil, is not hard. Whether you need to build soil fertility, control weeds, or attract beneficial insects, there's some basic techniques that you can employ to do all of it.
And those same techniques work when it comes to water.
In truth, it doesn't matter if your climate is rainy or arid, moist or dry, the health of your plants has much more to do with the condition of the soil they are growing in than how much water there is present. After a hard rain, healthy soil filters water and holds it like a sponge. In a dry spell, that same healthy soil can still retain moisture for weeks, even months.
To illustrate, I'll tell you a story of how Juan and I learned that healthy soil and diverse plants can handle even torrential rains that would be destructive otherwise.
Water is life, they say
When we began planting saplings here in Ecuador's cloud forest, where it rains an average of 4,500mm per year (nearly 200 inches), I watched with dismay as rust spots blighted their leaves and black fungus corroded their trunks. The water, I thought, all this water is killing my trees. Yet the locals confounded me with their philosophical acceptance of the pounding relentless rains. "El agua es la vida," they would say with genuine gratitude. Water is life.
I really started to think when we visited some mature food forest farms in our area. They were getting the same amount of rain, but their plants and trees were healthy, lush, and productive. Was too much water really the problem, or was it something else?
Walking through a mixed plantation of cacao and hundreds of other plant species, I could sense something different through the soles of my feet. On the land Juan and I were trying to reforest, the ground was clay hardpan in the dry season, and a boggy mudslide in the wet. By comparison, in this edible forest the ground felt yielding and absorbent. It's like a sponge, I realized, the soil is holding the water like a sponge. The plants can sip from it as needed, root to leaf. As if to confirm, a banana leaf unfurled above me, showering me in fine spray of water.
Interestingly, while strolling through this misty jungle of a farm, I recalled a time I spent in the arid desert of New Mexico. The friend who was graciously hosting me had a gorgeously xeriscaped small yard, full of delicate silvery plants, drought-tolerant berry bushes, and tiny but brilliant flowers. Beyond this mini-Eden, the immense red desert yawned, spotted here and there with cacti and sagebrush. The garden and the desert were receiving the same scant amount of rainfall, and my host did not irrigate. Despite the contrast, I intuited a similarity between the two scenarios: the xeriscaped garden and the dusty desert in New Mexico, the cacao food forest and my green desert of non-native grass in Ecuador. One could sustain a cornucopia of life, the other could not. What was making the critical difference?
Healthy Soil is the Key
Nearly all land-based ecosystems, whether wet or dry, have two things in common: earth and water. The earth can be sand, clay, loam, or rock. The water can be plentiful or scant. The intrinsic balance of an ecosystem depends on the ability of the soil to catch, conserve, and filter the available water to maintain life.
The "overwatered" backyard garden, the flooded prairie farm, and the degraded tropical forest all have the same problem. It's not too much water causing the peppers to bloat, the cornfields to flood, the saplings to drown, it's the inability of the soil to absorb, hold, and filtrate the water that is present.
Suburban lots are stripped of topsoil that is then trucked out, sterilized, and sold. Monoculture grain farms are subject to constant tillage, herbicide, insecticide, and chemical fertilizers, all of which kill soil life and turn soil into dust. When tropical forests are cleared, heavy rains quickly leach the soil of nutrients. In all three scenarios, the result is the same: soil damaged to the point where it can no longer maintain the level of moisture needed to sustain the life of the ecosystem literally grounded in it.
Water isn't life all by itself, but rather a crucial strand in the web. Water needs the living sponge of the soil and the plants growing in it just as much as they need the water.
If any part of the cycle is broken, the cycle collapses. A cactus in the desert is no more thirsty than a Brazil nut tree in the rainforest or a clump of cattails growing in a swamp. Each element, each strand of the web, exists in a delicate balance, held up by the other strands of the web.
How to Use Water
Where do we as humans fit in the web? What lessons can we learn from nature to catch, conserve, and use water optimally in our gardens and farms?
Conserve water in the soil.
Soil may appear to be heavy, dense stuff. But soil, like most matter, consists of more space than solids. Healthy soil is not uniform in its texture, but has clods called aggregates. These aggregates enable the soil to swell and hold vast amounts of water--and nutrients--in the spaces between the solids. Plant roots will sense the presence of nutrient-laced water and direct root growth towards it.
Whether you are working with an arid or rainy climate, the way to build healthy soil is the same: add organic matter. Really, I cannot emphasize it enough. Soil rich in organic matter holds moisture, boosts fertility, stores nutrients, cultivates soil life, and sequesters carbon.
Water so the soil can dry out
Plants don't thrive in perfectly consistent conditions. Nature is variable, even erratic at times, so plants have adapted accordingly.
The roots of plants are not like straws stuck in the ground. They are also living, dying, decomposing things that surge and wither with fluctuations of water in the soil. When it rains--or you water your garden--tiny hairs on the ends of roots drown and die. The plant opens its leaves to ”exhale” moisture above ground. As the soil dries out, the roots surge with growth below, and new root hairs plunge into the soil to suction the receding water. Intricate exchanges of sugars and enzymes funnel the nutrients from the soil up to the stem, foliage and fruit of the plant.
Once you understand this miraculous mechanism, you can better sense when to water your plants and when to let them do their subterranean work. Until your senses develop, you can always do "the finger test." Stick your index finger in the soil to just past the first knuckle. Even if the soil is dry on top, if the tip of your finger feels moisture, DO NOT WATER. There is plenty of water in the soil for the plants to take as they need.
Learn the water needs of your plants
Annual plants have tidy little root balls that sit comfortably in your garden's topsoil. Perennials have spreading clumps or strong tap roots that can bust through even tough clay to create pockets of space in the soil.
Water accordingly. Water annuals more often but with less water. Water perennials deeply but less frequently.
Water the soil, not the plant
When you water your garden, don't hose your plants down like you'd wash a car. Habitually drenching plants encourages stem rot, mold formation, and dreaded powdery mildew. Water plants in a six inch to one foot radius around their base depending on their size.
Cultivate diversity with an emphasis on native plants
Always plant a diversity of annuals and perennials in the garden. If all the plants' roots are sitting at the same level in the soil, you've created a competition. Encourage cooperation by planting a diversity of species with different water needs and root types.
Choose plants native to your area OR to a similar climate to optimize their ability to thrive with minimal intervention. For example, we grow many species from the equatorial Pacific Islands here in Ecuador's cloud forest. Mediterranean plants are a good choice for a Southern California garden. Cultivating plants that thrive in a similar climate expands your choices without compromising excess resources.
Use groundcover plants and mulches
In rainy climates, creeping groundcover plants and mulches protect topsoil by keeping it in place and preventing run-off.
In dry climates, groundcovers and mulches conserve moisture in the soil by shading it from the sun and preventing evaporation. Gravel and stone mulches are particularly helpful in arid areas that receive little rainfall. When temperatures drop in the evening, moisture condenses on stones and then flows slowly into the ground. If you have chosen your plants wisely, this should be all the moisture they need.
Water less as fruits develop
Finally, your plants don't need the same amount of water throughout their entire life cycle. Germinating seeds and new seedlings need soil to be kept moist. Once fully sprouted with a strong stem and true leaves, you can let the roots get stronger by letting the soil dry out in between waterings, but give them a good deep drink when you water them. As fruits form, back off a little more. Too much water inhibits sugars and starches from developing and you end up with soggy and tasteless fruit. Vitamin content will also be diluted.
As you gain experience, you will naturally develop a "feel" for when and how much to water. But there is simply no substitute for healthy soil and diversity when it comes to using water for obtaining optimal growth, flavor, and nutrition from your food forest.