Beware of that good looking bad soil

Editor’s note: Beginning today we will publish from time to time gardening information by Victoria Torley of Nuevo Arenal.

Welcome to Life is a tropical Garden. I suppose a few words of introduction are in order.

In 2012, I dragged my reluctant husband to Costa Rica, bribing him with a sailboat, and now we live between two volcanos.

We lived most of our lives in the U.S., where I gardened in New Jersey, torleyheader062314Ohio, upstate New York, and Georgia.  Each area has its own environment, its own soil, water, temperatures and pests.  And each has its own gardening demands.

Gardening habits had to change for each location, but those changes were nothing compared to the changes required when we  moved to the tropics. This is the first time I have lived in a country with only two seasons: rainy and dry.  Worse than that, we live near Lake Arenal where we have a rainy season and a rainier season with a few weeks of dry weather that occasionally sneak in.

So, how do you garden in the tropics? First, the most basic element.  Let’s talk about dirt versus garden soil.  Dirt can be just about anything, but soil is composed of inorganic material, organics (think compost), nutrients, fungi, animals (think worms), water, and, surprisingly, air.  About a quarter of garden soil is made up of air.  Air for the plants and animals that live in the soil and air between the particles of dirt that allows water to filter to plant roots.  Without an aerated soil, your chance of growing anything is small.

Some of our soil here looks marvelous.  I have a patch of rich-looking black soil that I dig out to use as fill in garden low spots.  There is just one problem.  From the surface and down 30 cm (about 15 inches), there are no worms.  None.  And, no matter how good your soil looks, if there are no worms, your soil does not have enough organic nutrients (think compost again) to be healthy.  Adding a commercial fertilizer will help plants grow but it won’t give you truly healthy garden soil.

Understand I have no qualms about adding commercial pelleted fertilizers.  No one has shown that plants can tell the difference between a prepared nitrogen molecule and one from rotted manure, but many of my friends still shudder at the mention of pelleted fertilizers.  However, I do agree with organic gardening friends that only fertilizers like compost provide an environment where worms can thrive.

So, how do you make healthy soil?  In New York, it was dirt, peat moss, and composted manure.  In Georgia, it was dirt, composted manure and soil amendment.  Here in Costa Rica, because of our varied environments, from black dirt to clay to sand, we need to make a lot of local adjustments.  Healthy garden soil needs few additions.  Sandy soil requires solid doses of compost and even some light clay to hold moisture.  And clay?  I had my clay dug out to a depth of 15 cm (about 8 inches).  Some of it I crushed and added to my black dirt (see above) with a lot of compost.     

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