I have a box of Fix-All wall patching compound. It is gypsum, lime, starch and some other inert ingredients. What would be a good formula for tomatoes? My tomatoes are growing very fast and setting fruit. I know they need calcium. Would this be good for other plants like peppers and cukes?
Not unless you know what sort of lime it is (the name represents several compounds) and what the 'inert' ingredients are and the various proportions. At a guess it is mostly gypsum (calcium sulphate) which is the core ingredient in most plaster products. This is pH neutral and supplies calcium, it is often used as a clay breaker. Other ingredients might not be so benign.
David
You should not apply lime unless you know your soil is acidic.
The soils in my area are quite alkaline. I broadcast sulfur and various sulfates every year and use acidic fertilizers. If I didn't, many of my plants would have chlorosis. My compost is actually leaf mold, which is more acidic than the usual compost.
Gypsum by itself is a good source of calcium, and it's quite inexpensive. Buy it and forget about using plaster.
Alternatively, dig bone meal into the soil before planting tomatoes. Dig it deeper than the existing tomato roots. Bone meal not only provides calcium; it also provides phosphorus, which promotes flowering and the subsequent formation of fruit. But to be effective, it must be placed where roots will find it since phosphorus does not readily dissolve and leach through the soil.
It says limestone. The soil pH is 6.2 according to my 7 dollar meter.
Paul
Your soil is almost neutral, being slightly acidic. I don't know about tomatoes, but it should be great for roses.
The pH of 6.2 is about right for veges so you don't want to be liming the soil. As DER said buy some gypsum if you are concerned that your tomatoes need calcium.
David
Isn't 7.0 neutral? What's a good source of gypsum? The small garden center I assume? I'm not trying to be flip but I can't even find bone meal at my local Lowes.
Paul
Oh goody, you've met. Think I'll just sit back and enjoy the show;O)
I noticed that, when I tried to buy gypsum at Home Depot, they wanted to sell me ornamental gypsum rock (little white stones). Soil gypsum is available in 50 lbb sacks for less than $10 at many larger garden nurseries. Orchard Supply Hardware (OSH) also carries it.
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