Being in our fifth year of business as Edible Landscapes of Cape Cod, we've probably done close to 100 consultations by now at peoples' homes and businesses, etc. One of the most common things we hear from people when they contact us is "My soil is so sandy. Is it even possible to grow a garden in this sand?" Although the conditions on Cape do make growing food a bit more challenging than other areas, we can say with absolute confidence that you surely can grow food if all you have is sandy soil to start with.
What to do about the sandy soil?
Sand is extremely porous. Sandy soil has a real hard time holding on to water and nutrients. When you look at a microscopic image of grains of sand compared to clay, silt and other soil life, you realize that the sand looks like giant boulders in comparison. "Soil organic matter" is the spongy glue that holds the soil together and gives soil the ability to hold on to water and nutrients. So the key is adding more "soil organic matter." Soil organic matter (SOM) is the organic matter component of soil, consisting of plant and animal residues at various stages of decomposition (dead plant material, root exudates, etc), cells and tissues of soil organisms (bacteria, nematodes, fungi, mites, beetles, worms, etc), and substances synthesized by soil organisms (their excrements, their decomposing bodies, etc.).
What can you add to your soil that is the highest in soil organic matter?
To many people this is no big news. But there are many gardeners out there (and homeowners we meet doing consultations) who just don't see the importance of adding organic matter/compost regularly. For us, we see the following scenario all too much: A person builds a raised bed or a small in-ground garden, maybe mixes in a few bags of compost or some fertilizer, plants some veggies. The first year they have great success. Then the next year, not quite as good. The following year still in decline. It may seem like a universal no-brainer to some that when you keep extracting (fruits, veggies, weeds, plant material) from your garden, your soil will have less and less of whatever nutrients/minerals you extracted. If there were 10 garden commandments, the first should be "thou shalt not extract more than thou can return to the soil." This is sort of a microcosm of our human dilemma here on earth. We deplete a resource then move on to the next patch of earth to conquer. Somewhere in there is a universal lesson that we live in a "closed-loop" system; a planet with finite resources. So whether we desire an ever-bearing garden or a human race that can live sustainably on this planet we must break our pattern of extract, extract! We must learn to nurture and give back!
So, back to gardening on sandy soil...
Here are some things you can do to make your soil more like a sponge and less like a sieve:
- Compost- We already said it, but its that important to mention again. If you have the space and ability to compost your food waste, that's a great way to "close the loop" and keep the organic matter high in the soil.
- Keep the soil covered- mulch is a general term for any organic material that covers the soil. It doesn't necessarily mean "brown bark mulch that you buy at the store," although that's better than leaving your soil bare. Mulch can be: leaves that fall from your trees in the fall, straw, hay, woodchips, grass clippings, even the weeds that you pull or chop from your garden can be used as mulch. The key takeaway here is that its always better to cover your soil year round than to leave it exposed to the elements. Also try to stay away from died mulches. Another type of mulch is a "living mulch" or cover crop, this can be a permanent/perennial ground cover type plant. Or, in a farm situation, cover crops are planted in areas that aren't being used to grow commercial crops. The cover crops hold the soil in place and keep the soil covered and thus spongy and alive.
- Go Organic- If you're going to fertilize, use organic fertilizer. Synthetic fertilizers are a short term fix. Like refined sugar, they may seem to produce the results we desire and seem harmless, but its only a short term fix. In reality the chemicals are actually frying the soil life and microbial diversity in the soil. Like the refined sugar seems fine and sweet but really causes inflammation in your body. Remember the soil microorganisms are the sponge! Speaking of sponge, consider applying biochar. This is a one-time soil amendment application. Microscopically char really looks like a sponge. With all it's "nooks and crannies" biochar creates the perfect living environment for microbial soil life that your plants depend on. Also speaking of amendments, consider adding lime to raise your pH. Most of the soils across the cape are on the acidic side and have a low pH. When the pH is too low, nutrients get locked up and the soil can be inhospitable to important microorganisms. Its always a good idea to get your soil tested to see what your baseline is for pH, so you know how much to add.
- go no-till- tilling or rototilling can be an effective way to break through some tough weeds or grass or whatever the case might be. We are not "anti-till," as sometimes it can be the best and easiest way to break ground. However, too much tilling can be damaging to the soil structure and microorganisms. Remember that we are trying to nurture spongy soil. Tilling rips apart your sponge! If you're keeping your soil fed with compost and covered with mulch, you shouldn't have to rototill. In compacted soils, we recommend hand tilling with a pitchfork or a broad fork (a giant two handled pitchfork used for loosening up the soil).
So there you have it. Edible Landscapes' tips and tricks for gardening in Cape Cod's sandy soil.
Edible Landscapes is in its fifth year here Cape Cod. The core team is Dave Scandurra, Marina Matos and Eric Fowler. Their mission is to make the Cape's landscape more edible one yard at a time.
They follow organic standards and often go beyond organic standards. They are "Accredited Organic Landcare Professionals," through NOFA (Northeast Organic Farming Association).
They also operate a small nursery specializing in hard-to-find edibles, perennials, herbs and more. They are available to answer your questions at firstname.lastname@example.org. You can also visit their website at www.ediblelandscapes.net.