The Barefoot Gardener: From the Ground Up, Part 3
October 13, 2017, 10:07 AM HST
* Updated September 8, 11:05 AM
Hopefully, you got a chance last weekend to break out your shovel or have an excavator come over with his backhoe, and you’re now looking at a big, dirty mess in your yard. Well, have the kids go get their little beach shovels because they’ll have lots of fun helping with this next part.
Get your rocks off
The next step to take on the path to fertile soil is rock removal. Removing the rocks makes the earth easier to dig and amend. I have found the best way to do this is to make a sifter.
Just pick up a 3-foot section of half-inch wire mesh at your local hardware store. You can either build a simple 2-by-4 frame and attach the mesh to the bottom of it (get as fancy as you want), or just use the mesh by itself.
Being I’m kind of lazy, I chose the latter, however you risk scratching up your arms using bare wire mesh.
Put on some heavy gardening gloves. Shoveling the dirt into a pile, clear an area in your garden-to-be.
Lay the mesh on the ground in the cleared area, and throw several shovelfuls of dirt onto it. Massage the dirt through the mesh sifter until there is nothing left except rocks and any debris too large to go through the mesh. Discard this stuff. I personally used the rocks and pebbles for a pathway.
Keep repeating this process until you have sifted all of the dirt that had been dug up. When you are finished, the entire garden bed should be filled with sifted soil. Remove and stray grass roots. You are now ready to turn dirt into garden soil.
Turning dirt into “Black Gold,” Part 1
The next step is amending the soil. All of the ratios I set forth are based on a tillage depth of 14 to 16 inches. If you have dug deeper, you will obviously need more amendment materials.
For all areas of the island, your shopping list is: organic chicken manure, one three-quarter cubic foot bag per 50 square feet; and organic compost, two to three cubic feet per 100 square feet. This can be bought in bulk if you have a pickup truck, or you can make your own, if you have the time to wait.
It’s almost impossible to use too much compost, so don’t worry about over-buying. Be more concerned about getting too little. You’ll also want Neem seed meal (follow application amounts on package) and a soil pH kit. Garden Exchange in Hilo carries both of these, and they are also available at many hardware stores around the island.
For dry, sandy areas, it is necessary to build up moisture retaining soil properties. Soil salinity is also a factor, so if you are near the ocean, you will need to amend a bit differently than inland areas.
For inland sandy areas, you will need add to the above list Canadian sphagnum peat moss, about one cubic foot per 50 square feet and vermiculite, one large bag per 75 square feet.
For shore and near-shore areas, it is recommended to have your soil saline level checked. Most vegetables will stress in salt levels higher than 2.5 (dS/m). In the meantime, take chicken manure off of your list because composted manure tends to have high salt levels. Mountain peat from Colorado and wood ash are also high in salt. It is especially important to consider salt levels if you intend to grow salt-sensitive plants such as raspberry, strawberry, beans, carrots or onions.
The University of Hawai‘i Extension: Agricultural Diagnostic Service can help out. Contact them in Hilo at (808) 959-9528 or check out their website. They can test the pH of your soil, or help you test it yourself.
Next week, I will continue discussing soil amendments for different types of soil.