pabyco
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15-0-15 fertilizer?

Hello Everyone, I had a soil test done recently on my garden as most everything won't grow well....I have done compost additions, grown and tilled in green manure, and the soil tests came back with very high phosphorus and calcium, high magnesium, and very low potassium. It has been recommended that I add a 15-0-15 fertilizer at 20lbs per 1,000 sq ft.

Is there an organic fert you could recommend? Or some combination of ferts? Or some other way to correct the imbalance?

Thanks, Paul

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rainbowgardener
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Re: 15-0-15 fertilizer?

Hardwood wood ash ("potash") is an excellent source of potassium. But it is quite alkaline and would change the PhD balance of your soil. Sometimes people deliberately add "lime" to make soil less acid, but if you don't need this, then consider greensand and/or kelp meal.

There are many organic sources of nitrogen for your soil, including poultry manure, feather meal, blood meal, fish emulsion, alfalfa meal, cottonseed meal, soybean meal.

I recommend you add them this way, don't look for one source for both, which will end up being chemical/ synthetic.
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pabyco
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Re: 15-0-15 fertilizer?

Can you provide any guidance on how much of each to add to approximate the 20 lbs per 1000 Sq ft?

Thanks, Paul

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rainbowgardener
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Re: 15-0-15 fertilizer?

well, using organics is different. They are slow release and can't burn your plants, so you can add more or less as much as you want/ can afford. One website suggested re the greensand: Recommended application is 2-4 pounds of greensand per 100 square feet or 1 ton per acre. For potting soils 5-20 pounds per cubic yard can be beneficial

Re cotton seed meal (for one example of organic N sources)

Cottonseed meal is a by-product of the cotton industry. After the cotton is pulled (ginned) from the boll the seed is crushed to extract the oil, what remains is further processed to become cotton seed meal and is used as animal and plant food.

As a granular fertilizer it is an excellent source of organic plant nutrients. When incorporated into the garden soil, cotton seed meal decomposes slowly releasing its rich supply of nitrogen, phosphorus, potash and numerous trace elements.

Because it is a slow-release, organic fertilizer, cottonseed meal is safe to use in all garden situations. It has a high organic matter content which helps to improve soil texture and build humus, it is good for loosening tight heavy soils and helps light sandy soils. Cottonseed meal holds moisture and nutrients well, thus promoting long lasting plant growth.

Knowing the pH of your garden soil before adding fertilizer is always a smart move, especially with certain organic fertilizers. Cotton seed meal is one of these because it can lower the pH level of soil. ...

below are some rough application rates for different garden situations.

light application for a garden that has been well maintained fertilizer wise is to till in 1-2 lb per 100 square feet.

Medium application for a garden that is in need of a boost is to till in 4-6 lb per 100 square feet.

Heavy application for a garden that is in poor shape, preferably applying after soil test, till in 10-12 lb per 100 square feet.

In all cases, work the meal into the soil with a tiller or spade in preparation for planting.
https://www.bettervegetablegardening.com ... -meal.html

So follow some kind of rough guidelines like that and see how your plants do. Early next year, get your soil tested again and see how it changed.

If you are gardening in the ground (not in raised beds or containers), it can be difficult to substantially change soil make up. Whatever you add is going to diffuse out into the native soil, so resign yourself to keep adding more each year for a few years, while you keep up what you have been doing with compost and green manure.

Good luck! Let us know what you do and how it works!
Twitter account I manage for local Sierra Club: https://twitter.com/CherokeeGroupSC Facebook page I manage for them: https://www.facebook.com/groups/65310596576/ Come and find me and lots of great information, inspiration

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