Making Garden Soil
The soil in this part of Arizona ranges from very sandy to mostly clay and soil pH also varies from farm to farm. Our soil happens to be quite sandy, with more clay as you dig deeper. Our soil pH is slightly alkaline, as is our well water. There is also caliche to be dealt with and a lot of rock to be removed. All in all the ground here is pretty hard and dry.
In order to get our garden growing we decided to build several raised garden beds and make our own soil. We also have in-ground garden beds where we are working and improving the soil with regular amending and fertilizing.
To the left is a photo of the beautiful, but rocky ground. To the right is an example of our garden soil after we've begun working and amending it.
We've chosen soil building materials that are available to us locally and can be found for free or purchased at a reasonable price. This is an overview of how we've prepared our soil for planting and what we use for fertilizer.
Sand is the primary material in our raised beds. Sand is an abundant resource for us because the high desert winds and rains continually replenish nearby sand deposits. We gather the sand in buckets or whellbarrows and transport it to our raised beds. It is fine, rock-free and has very little debris in it, because it has been sifted by the wind and rain.
Straw is readily available at the local feed store and is the second primary ingredient in our raised beds. The straw contributes to the looseness of the soil by preventing the sand from compacting. For the most part we compost the straw with manure before adding it to the garden beds. Leaves or pine needles would also make a good addition to our mix, though we don't have a local source for these materials.
This year we will be adding peat moss to some of our garden beds. To be honest I thought of adding the peat moss after we calculated how many buckets of sand we were going to need collect in order to fill our two new very long raised beds. (See construction photos below.) The peat moss will help the soil to stay moist, but aerated. I've read that there are sustainable alternatives to peat moss, such as coir coconut fiber that we may try in the future.
Goat manure is our primary fertilizer and is the third major ingredient in our raised beds. There is an abundance of goat manure available locally on nearby farms and we have made a point to get as much of it as possible. It has a lot of alfalfa hay mixed in and the manure that we have got has been really well composted and not hot at all. Generally we have mixed equal parts of goat manure, sand and straw to make the soil in our raised beds. The manure supplies the necessary nutrients to the soil and we add more or less depending on the vegetables that will be grown in that bed.
After the plants are established we side dress with goat manure if additional fertilizing is needed. Goat manure worked great in our garden last year and soon our farm will have its own supply. We will be getting our own goats later this summer not only for milking, but also for the manure.
As our rabbitry grows we will be adding more and more rabbit manure to the soil in our garden beds. One of the main reasons for getting our rabbitry started without delay was the recognition that we needed a source of fertilizer on our farm in order to maintain our garden. Rabbit manure is not hot and once collected can be immediately worked into garden soil or used as a side dressing to fertilize established plants. I also use rabbit manure when making soil for planting in containers
We use manure from our chickens as a fertilizer for our soil too. Our chicken manure is kept in a separate pile so that we can make sure that it has fully composted before we put it into the garden. To compost chicken manure we layer it with straw and rabbit manure and add water frequently. The high nitrogen in chicken manure breaks the straw down, and in turn the straw and rabbit mellow the intensity of the chicken. When composted we spread the chicken manure over a large area to further dilute its potency.
Most of our kitchen scraps go to the chickens, but there are some things that do wind up in the compost. Banana peels, citrus rinds, potato peelings, egg shells, coffee grounds all go into a compost pile. We add sand to keep the organic matter covered and prevent it from attracting flies. To speed up composting of tough kitchen scraps we water and turn the pile regularly. When the organic material appears to be broken down we add the compost to our garden beds and containers.
We brew compost tea for use as a fertilizer throughout the growing season. In a bucket or barrel we combine manure with water, wait about a week and then it is ready to use. We use the liquid manure to fertilize as needed throughout the garden and particularly for plants in containers. I've read that aerating the mixture during composting yields better results and we may experiment with a compost tea brewing device in the future.
I use a solution of fish emulsion and water during the growing season to fertilize established plants both in the garden and in the greenhouse. If plants look desperate for nutrients I use a spray bottle to foliar feed the leaves of the plant for a quick recovery. Alternately I use a watering can and simply pour the fish emulsion onto the soil around the plants.
We are interested in vermiculture and currently we are making preparations for a worm bed. Once the worms are established we will be able to harvest worm castings for use as a soil amendment and fertilizer. Adding worm castings or vermicompost to soil aerates and improves soil structure, and also provides nutrients to the soil in plant available form. We plan to feed our worms for the most part with rabbit manure, but may also include appropriate kitchen scraps.
Cover crops or green manures are another way to add nutrients into the soil and we are starting to experiment with those as well. This summer we will grow millet and buckwheat that we will turn back into the soil. Over the winter we will experiment with cover cropping oats, rye, mustard and hairy vetch.
Amending and enriching the soil as our garden grows will be an ongoing project. We'll be sure to post results from our cover cropping, vermiculture and compost tea brewing experiments as we get to them. Until then we'll be out in the garden learning from our plants.
Soil & Compost Books
For more on making soil and composting try these books:
More Gardening Topics