Hey. I'm getting ready to fill my growbags. They are all 20 and 30 gallon, about a hundred of them. The bottom I'm planning to fill with composting leaves, but I will need to make a mix for the top. I have access to these things in abundance:
1. coarse grade builder's sand
2. well composted horse manure
3. ground oak leaves.
I'm thinking about 1/3 of each of the above. Plan on using 10/10/10 fertilizer and watering with drip irrigation. Any ideas about how this soil mix will work for most plants (growing Thai vegetables for the most part).
Container growing in shade house
Soil is a composition material consisting of pulverized rock, clay and decomposed organic material. Your mix is missing the rock & clay elements that provide texture, moisture retention and minerals. Having grown up in S. FL., we had a dump truck of top soil dropped and spread on the St. Augustine lawn and landscape islands annually. This was necessary because everything organic leaches through sand so rapidly. I'd say you should start with 50% top soil from a reputable landscape company and then add your mix. Leaves make good mulch but it takes organic plant material as well to make compost. Also, I don't have a recipe for horse manure but I use all manure sparingly. I'm assuming the grow bags are because of nematodes??
Quote from MaypopLaurel :
Soil is a composition material consisting of pulverized rock, clay and decomposed organic material. Your mix is missing the rock & clay elements that provide texture, moisture retention and minerals. Having grown up in S. FL., we had a dump truck of top soil dropped and spread on the St. Augustine lawn and landscape islands annually. This was necessary because everything organic leaches through sand so rapidly. I'd say you should start with 50% top soil from a reputable landscape company and then add your mix. Leaves make good mulch but it takes organic plant material as well to make compost. Also, I don't have a recipe for horse manure but I use all manure sparingly. I'm assuming the grow bags are because of nematodes??
My soil has a hopelessly high PH. Oak leaves are slightly acidic. I cannot use more than 1/8 composted manure, as it has too many salts. There's no source for "clay". If you google it, you will only find ways to fix clay soils. Google sandy soils, you will see the remedy is organic matter. So the idea of adding clay doesn't seem to be recommended anywhere I can find it. I will agree that good black dirt from, say, Tennessee beats Florida soil hands down. That said, it's too pricey to get real topsoil on a practical basis. Most of what you have delivered is just organic matter and sand, which is what I can already make. I do have access to swamp muck.
I will always be fighting PH issues, since my well water is quite alkaline with limestone deposits. I have elemental sulfur to mix with my soil. When you buy soil, you never know quite what you're getting. I deal with a company that recycles concrete and they sell "soil", which is just the dirt washed off the concrete debris they are recycling. They screen it, grind it up. It appears to be black dirt, loaded with organic matter. But I'd rather keep that out of my food supply.
I'm going to be working with an ag extension agent this week.
Working with your local extension service is a good idea. They usually have sheets on growing specific crops too. I was suggesting that you could use more green manure (plant based compost) in addition to ground up leaves. Though dried leaves help aeration they are not a food supply for worms, etc. which provide castings.
Florida's limestone aquifers make for very hard water. Many growers install reverse osmosis systems. Some, such as Krull Smith, also use road aggregate mixes in potting soil.
Clay is elemental to Florida soils though in trace amounts. I grew up on a lake that had been a quarry and there were white clay veins throughout.
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