George’s Soil Recipe:
by George Giltner, Advanced Louisiana Master Gardener
- Compost (homemade or purchased)
- Garden soil (Not “potting soil”) Note: Your own top soil or soil from the garden is recommended.
- Expanded Shale
WHEN USING THIS SOIL MIXTURE FOR CONTAINER PLANTING:
If you have several containers you will want to mix up a batch of soil mixture and then fill your containers. In the bottom of your container(s), add about 2 inches of volcanic rock. This is called “Red Lava Rock” at most stores or garden centers. This rock allows for drainage and keeps the soil from coming out of the bottom of the pot, and it allows for oxygen.
The next thing you are going to do is mix up a batch of the soil mixture:
Use a wheelbarrow or other type large container and combine the following:
- Compost — Use a five-gallon bucket and put in 1 ½ buckets of compost in your mixing container. You can use your own compost or purchase some. (And you know we are going to tell you that your own homemade compost is best.)Garden Soil (Any will do, but your own is best.) (Use Five-Gallon Bucket and put in 1 ½ buckets).
- Garden Soil (Any will do, but your own is best.) (Use Five-Gallon Bucket and put in 1 ½ buckets).
- Expanded Shale (Use Five-Gallon Bucket and put in 1 ½ buckets).
- Zeolite (This is called “Horse Stall Refresher at Tractor Supply) (Use approximately 1 cup – it doesn’t take much of this.)
(Note: If you just want to use the mixture in one planter and not mix up a batch, you could just put in red lave rock, use a container such as a five-gallon bucket and add 1/3 expanded shale, 1/3 compost and 1/3 potting soil to fill the five-gallon bucket. Toss in a small handful of zeolite and mix this up. Use the mixture to fill your planting container.)
When you are ready to plant, fill your planting container(s) almost to the top with your mixture, allowing room to plant and to water. Add your plants and water in. The organics in the pot will have to be replenished as they break down over time.
WHEN USING EXPANDED SHALE SOIL MIXTURE FOR IN-GROUND GARDENING:
Obviously you will not be able to mix up large enough batch for in-ground planting. In this case you will just add a couple of inches of fresh compost, spread about two inches of expanded shale on the top, then sprinkle a light coat of Zeolite on top, then rototill in.
Explanation of why this Works:
- Compost is your nutrient source for plant fertility.
- Garden soil provides life (microbes to insects), nutrients, humus, minerals, etc. much like the compost.
- Expanded shale provides a large porous structure for air and water exchange, and it contains charge sites for nutrient retention (improves CEC). Roots need oxygen and a stable supply of water that expanded shale provides this.
- Zeolite is a group of minerals consisting of hydrated aluminosilicates of sodium, potassium, calcium, and barium. They can be readily dehydrated and rehydrated, and are used as cation exchangers and molecular sieves. Zeolite acts as a good binder for dry soil (for example soil that has too much organic matter and as a result it dries out). Zeolite will bind the soil and keeps it from drying out. Zeolite is much like expanded shale on steroids in a micro-sized granular form. It encourages bacterial life in rhizosphere of the root zone. Therefore your containers will have to be watered less, plants will grow healthier, and less nutrient amendments will be needed. Once the expanded shale and zeolite has been added, it does not break down like many other soil conditioners. These two soil conditioners have proven themselves in NASA Space Station experiments, and in down-to-earth gardens like the Dallas Arboretum.