By Don Trotter

Hello again fellow Earthlings, and welcome to spring!. Yes we're about to embark on another voyage into the undersoil world of Jacques Curly-eau. This week's adventure takes us into the mysterious realm of the coastal gardener in the flush of spring in beautiful Southern California. We will be looking at the soils these gardeners cultivate and make observations of the peculiar behaviors of the creatures known as Organic Gardeners...

O.K. I'm sorry, but I couldn't resist it any longer. I have been itching to do that for months, and now that the itch is scratched we can discuss this month's topic.

One of the most often discussed gardening subjects among coastal gardeners is the quality of the soils we are stuck with. Our soils are pretty funky in some areas of the county and particularly in areas where houses have been constructed on cut or filled soils that have been mechanically worked and transported for various development purposes.

These soils are not suited to sustain healthy plant growth for several reasons; one being the last time these soils saw the light of day dinosaurs probably roamed the earth. These soils are also mechanically compacted for purposes of stability, making them a little on the slow side when it comes to drainage and percolation of water. So it is the new homeowner (you) who is tasked with building a suitable topsoil from this existing material.

Not to worry! This issue's discussion is going to be about soil-building techniques for new and existing gardens. Many of you have been informed at one time or another that you have poor soils . . . Duh! And then almost in the same breath someone, an expert of course, has told you that in order to grow that garden you have always wanted you'll need to get rid of that poor soil and put in anywhere from 12" to 36" of new 'Topsoil.'

The next time you hear this, I have a suggestion . . . RUN AWAY!!! Unless the soil at your garden site is contaminated with toxic substances, there is nothing wrong with your soil that a little time and patience combined with a minimum of work cannot cure. Removing soil is labor intensive and transportation of dirt can be costly. But the main reason not to trade dirt is a little thing called soil interface. This is a condition that occurs when soils of different textures are put into the same space. If you made a bowl out of modeling clay and filled it with sand and then filled the bowl with water, what would you get? You're right!, you get a bowl of wet sand. That is exactly what happens when a layer of a porous soil is put on top of a non-porous soil. Then a whole new set of problems begins, including but not limited to, over saturation of the imported material.

Our soils are some of the best base materials for building a good garden soil. In many areas we have heavy clay-like soils that hold water very well. This can be a good thing, and it is really simple to build from this mucky stuff. Those of you closer to the beach are cursed with a very sandy material that drains away precious moisture too quickly. But this can also be resolved, and a soil with good moisture retention capacity can be built from this material.

I'm glad you asked. But first some science...
Once you get past all of the intellectual explanations, soil can be described as a complex natural material made from pulverized rocks and organic materials that provide nutrients, moisture and an anchorage for terrestrial or land plants. Soil is made of four basic components: mineral materials, organic matter, air and water. These four components are combined in many different amounts in many different soils and with different levels of moisture.

As a rule, a good soil in our area with an ideal moisture content is comprised of equal parts solid and pore space. The pore space is then equally divided by air and water. The optimum amount of organic material is between 5-7% of the solid matter. That is not too daunting a task to achieve. I'll tell you how.

The first formula is for those of you who are starting a new garden plot in sandy soil:
Per 100 square feet of garden space use:
20 cubic feet of organic compost -  I like Greenwaste. Contact your local waste company for a source of this valuable and inexpensive organic compost.
5  lbs. Bat or Seabird Guano
5  lbs. Soft rock phosphate
10 lbs. Gypsum
5  lbs. Greensand
10 lbs. Kelp enzyme (Kelzyme)
or Kelp Meal

Spread these products over the area and till into the top 6-8 inches of the existing soil with a roto-tiller or by hand digging. This is the only time you should ever till the garden. In the future you can let the organics and the earthworms do the aerating. Once this is done the garden is ready to plant. In about two to three months add 10 lbs. of Hoof and Horn meal to the garden by broadcasting, and then fertilize with a balanced organic about every 6 months. Remember to mulch the garden to save moisture. From this program you will see a change in the soil within the first year but by the third year and only six fertilizations you will have the garden soil you want. The soil will be rich in texture, dark in color and will hold moisture very well.

This formula is for those of you who have clay-like soils and are starting a new garden plot:
Per 100 square feet of garden space use:
16  Cubic feet of Organic compost - for this application I like peat moss.
25  lbs. Gypsum
25  lbs. Kelp enzyme (Kelzyme)
or Kelp Meal
10  lbs. Greensand
10  lbs. Bone Meal
15  lbs. Alfalfa Meal

Spread these products as indicated on the previous formula and incorporate into existing soil by rototilling. You can try to hand dig but you'll save time and backache by using a machine. Once this is accomplished the garden is ready to receive plant material. In 30-60 days apply 8 lbs. of cottonseed meal to the garden by broadcasting then in 6 months begin feeding with a balanced fertilizer. My favorite is 2 parts hoof and horn meal to one part Kelzyme at a rate of 10-15 lbs. per 100 sq. ft. of garden area every 6 months.

Remember to mulch; it is actually more important to provide a mulch layer in heavy soils so they do not form a crust that will repel water when it is applied. You will begin to see earthworms within the first 90 days after preparing the soil and within two years your soil will be amazing stuff that neighbors talk to each other about.

If your garden is established and your not happy with your sandy soil try this recipe for improving your earth.
Per 100 square feet of garden space:
5 lbs. Hoof and Horn Meal
5 lbs. Fish Meal
3 lbs. Kelzyme or Kelp Meal
3 lbs. Cottonseed Meal

Broadcast this mixture over your garden and water thoroughly. After watering apply a minimum of two inches of organic mulch over all exposed soil and water again. Repeat applications at six month intervals. If your plants show any nutrient deficiencies you should apply a mineral supplement at the time of scheduled fertilization. You'll see a difference within the first four months.

If your established garden is in clayish soil this blend will help.
Per 100 square feet of garden space:
5 lbs. Gypsum
5 lbs. Kelzyme or kelp meal
5 lbs. Greensand
5 lbs. Sul-Po-Mag
4 lbs  Humic acid based organic fertilizer (Grow Power)

Use this mix exactly as the above recipe however you should not add Greensand more than once a year, so skip the Greensand on the next feeding and in its place use 4 lbs of alfalfa meal. Mulch as described above and repeat at six-month intervals.

A good thing to remember about using organic fertilizers is that the release their nutrients over a long period of time so you don't need to feed nearly as often. You will be saving time and money by slowly changing the soil that you already have, while learning the environmental benefits of using non-chemical products in your garden. More birds and other cool wildlife will be more frequent visitors and, you get the satisfaction of knowing that your personal environment is free of chemicals that harm the natural ecology of our area.

Next time we will be discussing how to treat your roses during the dog days of summer. See you in the garden!

Don Trotter operates The Organic Gardener's Resource Centre and is a consulting horticulturist and an award-winning garden designer. You can reach Don toll free at (888) 514-4004 or email him at    He is always available to talk dirt.

Return to the May/June Issue Index page