Too much compost?

[frdnicholas]

This past fall I added compost from my tumbler with some rock phosphate to the place I plan tomatoes. If I add more compost this spring, is it possible to be too much for the tomatoes to make good fruit? I mixed a trowel full of compost into the soil with the rock phosphate. I remember reading that too much nitrogen with pepper plants gave great leaves but less fruit. Could that be the problem with too much compost? The soil was Miracle-Grow soil about one year old. It is in a 4x4 garden bag about 12 inches deep.

 

[Chuck]

About 30% compost is max. Excess nitrogen comes from fertilizers not compost. Too much compost actually deletes nitrogen

 

[frdnicholas]

How do I measure 30%? I could just eyeball it I guess.

 

[Chuck]

How do I measure 30%? I could just eyeball it I guess.

Eyeballing is close enough. I try to keep my compost at 20-25%. It all depends on the degree of decomposition of the compost but really try to not get above 30%

 

[frdnicholas]

Can you tell me more about how too much compost uses nitrogen?

 

[Chuck]

Can you tell me more about how too much compost uses nitrogen?

It's a little complicated but I'll try to explain. Most of todays store bought composts are not true composts. By this I mean that all of the organic matter has not been broken down sufficiently. A true compost has a carbon to nitrogen ration of 10 to 1 or less. When you purchase a bag of compost and it has wood chips and splinters or substantial pieces of organic matter in it, it will have a carbon to nitrogen ratio of about 20 to 1. Soil microbes need nitrogen for the energy needed to break down all of this organic matter and a 20-1 ratio does not have enough nitrogen for BOTH the breakdown of the organic matter AND/OR enough nitrogen for proper plant growth. I could have used a better word than to say deletes nitrogen in my previous post. A better word would be a nitrogen tie up. The nitrogen is there but it is being tied up by the soil microbes. Does this make any sense?

 

[frdnicholas]

My compost was made in my compost tumbler. As far as I can see, everything seemed to be broken down, so hopefully it won't need much additional nitrogen from the soil. Would it also help to add some blood meal before planting? It's only available commercially, but it might still be a good source of nitrogen? I am so grateful for your help and clear explanations.

 

[Chuck]

My compost was made in my compost tumbler. As far as I can see, everything seemed to be broken down, so hopefully it won't need much additional nitrogen from the soil. Would it also help to add some blood meal before planting? It's only available commercially, but it might still be a good source of nitrogen? I am so grateful for your help and clear explanations.

Even good finished compost does not have sufficient nitrogen levels for proper plant nutrition. You will still need to add fertilizer. Blood meal is a great source of nitrogen but it lacks P and K. And the cost of blood meal is rather high too. IMO you would be much better off by using a good all purpose organic fertilizer. I only use blood meal when I see one of my plants needing additional nitrogen. It is fast acting and must be carefully used.

 

[frdnicholas]

Can you recommend a good source for organic fertilizer? I've been using Miracle-Grow soil which says it has fertilizer, but if I can find something more organic around here in Southeast Coastal Georgia, I would prefer to use that, if it's not cost prohibitive.

 

[Chuck]

Can you recommend a good source for organic fertilizer? I've been using Miracle-Grow soil which says it has fertilizer, but if I can find something more organic around here in Southeast Coastal Georgia, I would prefer to use that, if it's not cost prohibitive.

Check feed stores, nurseries and hardware stores. Organic fertilizers are BIG in the US now so it shouldn't be a problem. Just make sure that whatever you buy has OMRI somewhere on the package. And it is everywhere online.

 

[frdnicholas]

What does the OMRI stand for?

 

[Chuck]

What does the OMRI stand for?

Organic Materials Review Institute. They make sure that when something is said to be organic it really is.