I have been preaching about the importance of keeping your soil alive, aerobic, and organic. No-dig gardening and the concepts that go into the practice encourage healthy soil building. Let me emphasize the term SOIL BUILDING. This is what organic gardening is all about. Almost no matter where you live, soil has been ruined by human activity: when homes were built, the soil was compacted, and often questionable materials dumped into the ground. After homes are finished being built, even MORE compaction occurs. Most organic material that is found is usually raked up. If anything is grown, chemical fertilizers and pesticides are often sprayed, the soil organisms suffer. People drive and walk all over the ground and bare soil bakes in the sun with no layers of mulch to protect it. Whatever the tractors leave unmolested, homeowners are often there to finish the job.
No wonder when people plant things in such conditions they often get discouraged. Not many plants love bone dry dirt, exposed to the elements, excluding worms and beneficial organisms. And no wonder people have to dump so much water on these plants. There are no layers to keep moisture in tact. When the soil profile is all the same texture, water gets pulled out quickly. If there is a layer of mulch to keep the sun off the soil, and varying layers of texture, water doesn’t evaporate so quickly.
In soil that is compacted and poisoned, oxygen is low. This is a haven for pathogens and anaerobic microorganisms, most of which are not good for people or plants. There are several general concepts you want to keep in mind when making a no-dig garden bed:
- avoid activity that compacts the soil and/or decreases the oxygen-avoid overwatering, don’t walk in garden beds, make sure there is good drainage.
- make sure there is food for everyone: compost should be a good mix of food for bacterial and fungi. You can also add some raw material in the bottom that can help with this. I will explain below.
- inoculate your bed with microorganisms. There are many sources of inoculants for bacteria, fungi, nematodes and more to help get your population of good critters going. Try Fungi Perfecti’s MycoGrow™ Mycorrhizal Fungus Products or Arbico’s beneficial nematodes Arbico is based out of Tucson but handles orders via mail order. If you follow my instructions below, you can definitely add Alabama Jumper worms, the best worms for putting directly into the garden.
- mulch soils around plants to encourage water retention. Use a mixture of compost and mulches that will break down and provide food for your plants. A reminder: compost is a rich mixture of broken down materials, usually done with proper thermal composting techniques or using vermiculture (worm composting). Mulch is any material that is used to block the sun off of the soil surface. Sometimes compost acts as mulch, but not all mulches are sufficient as compost.
- Stop digging. This is especially important for fungi, which are greatly disturbed by digging. Plowing also causes compaction. Below where a plow turns soil a layer of compact soil becomes a haven for anaerobic activity. Luckily for us, not too many growers who are reading this use plows, I assume.
- Don’t use heavy salts, inorganic fertilizers, or pesticides. They kill microorganisms that feed your plants. The organic activity that occurs in soil will free up all the nutrients your plants need, provided you don’t overwater. Watch out! Many fertilizers that are called “natural” are organic fertilizers mixed with synthetic or mined salts. Make sure your fertilizer is REALLY organic. A hint: real organic fertilizers are usually not mixes. They are usually a natural product you can identify, often ground up.
Now I am going to suggest one method of implementing a no dig garden that will help you get started. This method is inspired from what is being done around the country, but I have made some changes to meet our desert challenges. Unfortunately in the beginning, especially in our desert soils, you probably will need to dig. And I won’t lie, this is a bit of work, especially doing the initial dig. But if you do things correctly, you may never need to dig again, and planting in the future will be easier than it ever was before.
THE FIRST SEASON
- Mark off the bed. It’s a good idea to lie longways north and south. On the North end of the garden, you will put your tall crops. Your shorter crops will be on the south side. This ensures that plants all get the right amount of light, as the sun is usually slightly more south. The closer to summer we get, the more directly overhead the sun will be, but we still try to avoid shading out plants in this way.
- When you plan out the WIDTH of the garden, make it so on each side you can reach to the middle without too much trouble. This will help prevent you from being tempted to step into the garden. Measure this out by reaching in and where you can reach to is the middle. For me, this is about 5 feet wide, but you might want to have your bed slightly less wide.
- Dig out all the soil to about 2 feet deep. Save some of it and use the other soil to make humps around the perimeter of the garden.
- Make sure the drainage is there. Sometimes you might have a caliche layer that will need to be broken up. In fact, you might find all sorts of strange stuff below the soil. Remove any automobile parts, large stones, and whatever else you find in the bed you don’t want in the garden. Caliche can be a LOT of work to break up. Caliche is basically a layer of calcium carbonate. You might need to employ a mattock pick or caliche bar, which is a big heavy bar used to break up such layers of hard rock.
- If you cannot dig this deep, you might consider raising the bed to compensate for the loss of depth. Just ensure the water drains out of whatever hole you CAN dig.
- When your hole is dug up, put a layer of completed compost in the bottom 6 inches of the hole. Do not tamp it down, leave it fluffy but even.
- Put Alabama Jumper earthworms in the soil. How many you use is up to you, but gauge it by the size of the bed you are making. It’s not an exact science. With the worms put in about 4 inches of green waste and shredded newspaper (not the glossy kind). Green waste can be kitchen scraps, mostly vegetables, grass, and pulled weeds (no bermuda grass). Do this quickly. Worms hate light and can die if you leave them out too long.
- Put a 3 inch layer of straw on top of the green waste and worms.
- Fill the hole up with about 50% soil and 50% compost, keeping everything nice and fluffy. Don’t tamp down the soil very much because if you make conditions for the worms too compacted, they will be deprived of oxygen.
- Level out the soil gingerly with a nice steel garden rake (not a leaf rake) and begin to plant seeds and plants.
- Around plants add a layer of compost and a layer of straw. See illustration. Do not mulch planted seeds until they have germinated and you have thinned them to the proper distance apart. Once they are large enough, you can add mulch. Avoid putting compost on the base of the plant (except for plants that don’t mind being buried deeper like tomatoes and eggplants). Straw is ok at the base of plants, however.
- Add any stakes, lattices, or other structures you might need as you need them.
- When you feed throughout the season, always feed from the top. Even if you use powdered fertilizers, avoid digging them in. Just let the water push the nutriment down. Eventually this food will reach the root zone.
As I said, avoid ever stepping in the planted area. Use the planned perimeter as your walking space always.
THE SECOND SEASON
When it is time for you to plant again, you will not dig up the garden. Instead you can follow these instructions:
- Clear out any plants you dont want to keep. It’s not a bad idea to keep a few around, but keep in mind you will need to work around them. Do not DIG up plants and leave the mulch from the season before where it is. Throw discarded plants in compost. Remove any structures that might be in the way, like tomato cages or lattices that are no longer being used.
- Make a mixture of 50% soil (get soil from another part of the yard) and 50% compost–enough to cover the top few inches of your bed. Add any ORGANIC ammendments you find appropriate for what you are growing: kelp, bone and blood meal, composted bat guano, worm castings, cottonseed meal, feather meal, fish meal… Just make sure it’s appropriate for your plants, like don’t use something higher in nitrogen for a root crop.
- Take your mixture and add it to the bed. Any plants you have left behind, work around. Most plants don’t want to be buried deeper, though as stated before, some are ok with this, like tomatoes and eggplant.
- Plant out the bed with transplants and/or seeds.
- Mulch as described in the first season: once again, wait to mulch seeded crops AFTER they have germinated and have been thinned. If you want to add more red wiggler worms, put them in now, below this mulch layer. If you do this, add shredded newspaper (once again, not the glossy kind).
- Set up structures for your plants to grow on.
- As described above, when you feed throughout the season, feed from above. The point of a no-dig garden is to avoid digging.
- As each season wears on you might find your bed getting higher. You can raise beds to compensate for this rise in soil.
- If you are growing crops like peas, or root crops like beets, radishes and carrots, deemphasize the compost. You can add just soil on the top layer as these crops don’t need super rich soil.