“From my perspective there is more interest in greywater now than ten years ago. People recognize their used shower water can be beneficial to their landscapes, and the awareness is growing that we can't continue wasting and polluting water the way we've done in the past. Our relationship to water must change, and greywater is a piece of that transformation.”
-- Use Greywater Now: Planetshifter.com’s Interview with Laura Allen from Greywater Action
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Discuss your active vs. passive techniques for water re-use?
My techniques are all passive. Diverting greywater, storing rainwater (in tanks but especially in the soil). Then there are simple ways of being creative with water indoors, such as putting a few bricks in the toilet tank to limit its refill volume, and using kitchen sink water for compost heaps or perennial beds. Another one is to keep a bucket in the shower to catch the first bit of water, before the shower heats up. After a few showers the bucket is 3/4 full and can be poured into the toilet TANK as soon as it begins to refill, after flushing.
Should a home gardener calculate the moisture content of their soil? If so, how?
I wouldn’t bother using more than a finger to test the moisture. If it’s wet an inch or so below the surface, the roots have access to water. I’m often asked how long to program irrigation timers for. It’s surprising that most people assume around 30-minute durations as a starting point, several times a week. A rule of thumb for me is no more than 10 minutes a day, early in the morning, once or twice a week. If you really want to be conservative, give everything a good watering and then shut your irrigation off completely. Observe your plants. What are they telling you? How long before they begin to wilt and look thirsty? Find out how long your garden can go in a heat spell without water, and you’ll have your duration. Again, if you do this in a heat spell then you will be able to dial it down even more in milder weather conditions.
What is your take on the water restrictions in places around the Bay Area? Do you police your neighborhood?
I did recently call EBMUD on an apartment complex across the street from me actually! There was a geyser going off every couple of days (broken irrigation head), and the problem was that no one could tell me who the property owner was, otherwise I’d have contacted them directly. But no, in general I don’t police anyone. I’m more concerned about agricultural use really than I am residential. Commercial agriculture uses 50 to 80% of the state’s water, depending on who’s telling it, and this is done in seriously inefficient ways. Much is used just to wash the insects and dirt off of the harvested crops, and the overhead-sprinkler irrigation that is widely used causes much of the water to be windswept and evaporated before it hits the ground.
What types of Bay Area food crops are faster to a yield in a hobby garden?
Radishes are fast and fairly drought-tolerant. I’m a big fan of perennial vegetables. Sunchoke, artichoke, and tree collards, for instance, withstand drought fairly well. The latter can live for a decade and provide protein-dense food 24/7 for the entire time. I can’t say that for many garden plants.
Growing food in general, whether or not they are particularly drought-tolerant plants, saves us water in the long run. For the reasons I mentioned about commercial agriculture, we can save a lot of water by growing as much of our own food as we can instead of supporting wasteful agriculture practices. This in turn would lead to a scaling-down of larger farms, which in turn would force those farms to focus more on quality in order to survive.
But I do also think we should focus on drought-tolerant crop plants. Some of my favorites to work with are resilient in the face of drought:
fig, olive, pomegranate, loquat, jujube, strawberry fruit tree, feijoa (or pineapple guava), carob, black walnut, blackberry, grape (blackberry and grape both have native CA varieties), prickly pear cactus, rosemary, thyme, oregano
How can I build hydrophilic soil on a sun-drenched, fried-out and nutrient-deficient city lot?
The most important thing is to keep the soil surface covered! Think of the soil as a child. If you saw a naked child lying there exposed to the elements, your instinct would be to throw a blanket over it.
Whether it’s by adding tons of organic matter (compost) or dumping a few inches or more of wood chips or straw on your planting area, the ground needs to be covered to reduce evaporation. You can also do a living mulch – that is to cover the ground with vegetation. The simplest way to do this is to use a common cover crop such as red clover, or any member of the bean/pea family. Just get a huge bag of your favorite beans next time you are at the store, and the next time it’s about to rain, till the surface of your soil and scatter the seeds by hand.
They must be kept moist after their initial contact with water, so you may have to plan to have someone water heavily if the rain subsides over the next few days. But soon you will have a nice green carpet protecting your soil. Not only do mulches (living or not) protect the ground and your plants from drying out, they provide several other functions.
The most obvious is that you don’t track mud in the house when you don’t have bare, exposed soil everywhere. Another is that erosion is minimized. A single raindrop hits the ground with enormous force, and without a matrix of fungi and plant roots to absorb the impact, the topsoil gets washed away. Having a buffer to absorb that shock and send the drops gently to the ground keeps the soil in place. So notice here I mentioned two benefits of using live mulches (this can be anything, trees, shrubs, anything).
1) The aboveground parts of the plants act as a shock absorber for the impact of the rain.
2) The roots and associated microbes form a sponge-like, porous soil surface that absorbs water.
And to reiterate what I said before, adding organic matter, compost, to your soil is probably the surest way to turn your soil hydrophilic (water-loving). Compost is said to be able to hold up to 20 times its weight in water! Combine this with an evaporation shield (mulch) and you get to store all of that water right in the ground where your plants can access it at leisure. Yet another function of mulch is creating habitat for beneficial insects and microbes. This is a whole topic unto itself.
A healthy micro-biome is critical to a garden’s health. Look into the work of Dr. Elaine Ingham and the Soil Food Web movement for more info. And finally, mulching reduces weeds! Nature abhors a vacuum, so if you leave a place exposed nature will put something there to cover it. Find a sprawling groundcover plant that you really like and use it to fill that niche instead. It’s not a weed if you intend it to be there. Sheet-mulching (applying cardboard before the woodchips) in my experience reduces the presence of weeds by probably 95%.
What the hell do I do with my compost? I don’t have a garden….
Start or join a community garden. There are vacant lots everywhere. Or see how many tomatoes you can grow on your patio or balcony. They make little compost tumblers for these situations. Worm bins are also a fun and (and more kid-friendly) way to turn your kitchen scraps into black gold. Chickens also will make good use of your food scraps.
I saw a video online about sheet mulching. Is this typically a group effort? Isn‘t the ink on the cardboard toxic to the soil?
It certainly is more fun when it’s a group effort, but it’s an extremely low-labor task compared to most other gardening jobs. Cardboard is free, too. Bicycle shops, big appliance stores, any place that deals with large boxes is usually happy to give it away. They also sell rolls of it at hardware stores if you don’t like breaking boxes down. As for the ink, there is some controversy of opinion there. Some believe that the inky chemicals are neutralized by the soil fungi pretty immediately. But the issue is largely irrelevant to me, since its only tender annuals like lettuce and things that you’d be worried about, and annual beds don’t get sheet mulched just because it would be such a hassle to dig through it twice a year. Instead a simple layer of straw is usually used.
For larger areas such as patios and paths, as well as areas planted with perennials, even fruiting trees, vines and shrubs, cardboard is considered safer. Plants have barriers that don’t allow toxins to enter the fruit. This is why they tell you that if you have lead contamination not to plant leaf- or root-vegetables, but fruit is generally thought to be okay. I would love to see some scientific research in this area.
My neighbor has seriously neglected his sprinkler system. There are exposed black plastic pipes all over the beds and the lawn. How would you start to access this scene?
As I said, keep everything covered. The sprinklers can be converted to drip, which instead of spraying indiscriminately everywhere, sends small amounts of water to each plant. Having even drip tubes exposed to the sun, however, will shorten their life. Keep everything covered.
There are lots of water-conserving techniques out there. Google some of these:
Ollas – unglazed clay pots with narrow necks, and without holes - and fill them with water. They attract sub-surface plant roots which suck water from them as needed, never wasting any.
Wicking Beds – raised beds which are irrigated from beneath the plant root zone and wick up moisture, seriously reducing the sun’s evaporative effects.
Sunken Beds – beds that are lower than the surrounding paths. Water naturally flows down into them rather than running off quickly, as in most raised beds.
Swales – contour ditches that catch and store water for a few days, allowing it to seep into the ground, recharging the landscape.
Curb Cuts – using a concrete saw to open sections of street curbs to channel street flow from rain events into gardens.
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Jeremy Watts is the owner of Food Forest Design Works, an ecological gardening and consulting business in the San Francisco Bay Area. He holds certificates in Landscape Horticulture, Nursery Management and Permaculture Design from Merritt College in Oakland, as well as a Greywater Specialist Certification from the EPA- approved QWEL (Quality Water-Efficient Landscaper) program. He has studied broad-scale water-management strategies with Darren Doherty (author of the Regrarians Handbook) and Mark Shepard (author of Restoration Agriculture), and co-operates a small fruit tree nursery in Oakland.
Jeremy Watts, Owner
Food Forest Design Works
Jeremyjwatts at gmail.com