Compost too potent?

[wsommariva]

Hi everyone,

I've been making my own compost for a few years. We now get monster hostas and butterfly bushes. My wife thinks my compost is too "powerful" and wants to limit it's use. I want to spread it on my flower beds generously each spring to improve the bagged topsoil that is it's main base.

Compost is 80% oak leaves, the rest being grass clippings and kitchen scraps.

Any thoughts?

Thanks

[imafan26]

I wish I had some of that potent stuff in my yard. Oak leaves probably makes a more neutral to acidic compost and most plants like a slightly acidic soil. It also will retain a lot of moisture so I would say you have some very happy hostas.

[tomc]

Most compost that is over much full of nitrogen, is much stinkier than the average American is willing to apply near the house.

[wsommariva]

No doesn't smell at all.

[rainbowgardener]

It is very difficult to have compost that is "too potent," unless you put a lot of manure in it and don't give time for the manure to break down. But then as noted, you would know that by the smell.

The nutrients in compost are in biological form not chemical, therefore they are released slowly over time as the compost continues to break down.

[imafan26]

What did you use for fertilizer?

[wsommariva]

I don't use fertilizer now that I use my compost

[imafan26]

You either have a very active soil web or you have got really potent compost.

I could not feed my garden on compost alone. In fact, the compost that is commercially available here from green waste is unfinished sometimes and will steal nitrogen from young plants. I am not totally organic, I do use fertilizer. I did use blood meal as a nitrogen source, I don't use manures. Sometimes, I use fish emulsion sometimes but the neighbors don't like it and my soil test says in all of the plots I only need nitrogen so I primarily use sulfate of ammonia. It is hard to get an organic source that has a good amount of nitrogen and zero phosphorus. I have gotten Scott's organic lawn fertilizer. It has 11% slow release nitrogen but it also has phosphorus. My soil tests phosphorus between 450 and 2000 ppm. I only need 37 ppm. I probably do not need to add any phosphorus for years.

The compost here tests at a pH 7.8. which would not be good for the alkaline plots but is o.k. for the acidic one.

[toxcrusadr]

What, your plants are too big and healthy? Wish I had that problem. Hrrmph.

If it ain't broke, don't fix it.

[rot]

..
Well I'm envious. The soil 'round here, in sunny, dry, So Cal seems to just drink all the compost I can give it.

I expect the soil is much different here than in No NJ and it's a lot wetter there too but, I'm wondering if the fact that winter here is different and that everything doesn't go dormant for winter has something do with how compost is rapidly consumed in the garden. Mulching helps but I have enough trouble making compost to keep up with the mulching.

Otherwise there's a guy on another board that says you shouldn't have more than 5% organic matter in your soil. Near as I can tell, I'm in no danger of that.

Enjoy your butterfly bushes. Mine got munched pretty good this season so we'll see if they start coming back in February - March.

to sense
..

[wsommariva]

Thanks for all your thoughts. I think I'll continue with my annual plan and keep watching how things grow.

I forgot that I do use rose fert and a general fert for my lilac bush.

[toxcrusadr]

The OP may want to get a soil test at some point. If you've been adding compost year after year, what's actually going on? If things are growing great, maybe you don't need to, but if you need to convince the dear wife it's not too much, $20 at the local ag extension service might do it.

I added compost, ash and some fertilizers to my horrible clay for 20 years, tested it and found that P and K were very high. So for awhile I'm going to limit compost, and avoid high P and K fertlizers like the big bag of soluble 20-30-10 that I got somewhere. If the plants seem to need nitrogen, I'll add a high N, low P and K fertilizer like 29-3-3 lawn fert or ammonium nitrate.

So a soil test can tell you things...

[wsommariva]

I was thinking about a soil test. I got one for my lawn soil two years ago and it was an eye opener.....way too much lime I was adding.

For my compost - oak leaves/grass and kitchen scraps, any general idea of what's in it as far as N P K?

[tomc]

For my compost - oak leaves/grass and kitchen scraps, any general idea of what's in it as far as N P K?

Compost that tests higher than about 2-2-1 is a rare thing.

[wsommariva]

Good to know thank you.

[toxcrusadr]

I agree with that, most compost is in the 0.5% - 2% range on N, P and K. But it's hard to know what NPK levels actually are in your soil after adding it (and having your plants subtract it) over time. N goes up and down seasonally and is lost to leaching and atmospheric release as well as to plants...and K and micronutrients (Fe, Mn etc.) are subject to leaching...P is the only one that hangs around much because it sticks to the soil better.

Also, .5-.5-.5 sounds so low, but on the other hand, we add wheelbarrows of the stuff, so the total amount in pounds does add up.