Here in Madison, Wisconsin, our native soil is high in clay. It can be dug and worked when it is dry, but it is sticky when damp. However, our garden plot, which gets 20 to 30 gallons of compost every spring, is easy to dig and work, even when damp. The clay is still in there, but the fibrous compost keeps some of the clay particles separate from each other. so the soil does not clump or stick to the shovel. Our clay has most, if not all, of the minerals that plants need, so we have never added any fertilizer. That is, we have never added granular fertilizer that contains nitrogen, potassium, and phosphorous. However, I grow blueberries, and I use granulated sulfur to lower soil pH in the vicinity of these shrubs. I also use Schultz's Plant Food, a comprehensive fertilizer, in small amounts, to keep these shrubs healthy and productive. I'm not sure this is really necessary, however. If you have clay soil, chances are that most of the minerals plants need are already present. If you have sandy soil, you might need both compost and fertilizer to have a successful garden.

In general - fertilizer = feed the plant; compost = feed the soil, grow healthy plants. Fertilizer means you are adding stuff - purchased stuff - all the time. You can grow your own compost; no $$.

There are many different NPK %s assigned to finished compost, depending on who you listen to, but you can be sure the values are very low - somewhere around 1-.5-.5.

Al

I've been adding compost (some store bought and other I've made myself (mainly leaves and grass). I was told that compost was all you need for your beds and lawn. If you enrich the soil, you don't need to add extra. NOw today I was told something different and I'm not sure what to think.

I had a simple soil test done at a local farming supply company. I was told that the PH level in my two beds were good, the lawn was really low (5.4). But, he told me that my general nutrient levels were really low in both areas and that I needed to add fertilizer to everything.

Can someone explain? Sorry for jumping in to this post but I think it pertains to the main question.

reply to forensicmom

no expert here but a few questions:

1. how long have you been adding compost?

2. do you top dress it or till it in?

3. What were they trying to sell you?

FM - if you're consistently removing more nutrients from your gardens in the form of plant mass than you are returning in the form of compost/soil amendments, you'll have a net loss of some nutrients; so fertilizer or soil amendments that either target the deficient nutrients or cover a wider spectrum might be required for normal growth. Even if you composted every scrap of plant matter that you removed from your garden, then returned the compost to the garden, there would still be a net loss of nutrients due to volatility and leaching.

Al

Because teh nutrients in compost are not readily soluble you do not get good nutrient values if compost is tested and compost supplies many more nutrients then a synthetic fertilizer does. Most all synthetic fertilizers supply only Nitrogen, Phosphorus, and Potash, sometimes iron, and a few may supply many more in water soluble form which means the nutrients can be washed out of soil pretty quickly. that is why compost, and other forms of organic matter are better for plants then synthetic fertilizers would be.
Some research today is indicating that plants do not easily utilize the synthetic fertilzers as was once thought.

Hi greenskin.

Compost has an analysis of something in the range of 1-2-2 or thereabouts. Fertilizer is usually 5-5-5 or higher.

Compost is considered a soil amendment, not so much a fertilizer.

When I make a new garden bed I throw in some Phosphate as a fertilizer and amend the soil with compost and other additives. My soil is naturally good for the Potassium levels.

Greenskin, I see that you live in Boznia/Herzegovina. When gardening, and attempting to create the best possible soil for growing healthy plants, the place to begin is finding out as much as you can about the natural history of the area. If the soil contains clay, it might have been the bottom of a lake at one time. If the soil is acidic in pH, it might be mainly volcanic ash. If the soil has high levels of silt, it could have been a river bed in the past. If the soil has high levels of organic matter, it must have been either a forest or a grassland for many thousands of years. If there is a lot of gravel, or rounded rocks, then glacial deposition is likely. Are there limestone deposits in your area? If so, you might have hard water, and you might have soil that is high in calcium and magnesium, with an elevated pH, maybe 7.5.

Thank you all for your replies. You have cleared my doubts.

Can someone tell me, why it is not allowed to add ash and cooked vegetable food leftovers as a composting material?

Wood ash is about 50 percent Calcium Carbonate, lime, and if not added to a compost pile carefully that can easily disrupt the bacteria that are digestng your material. Old school though was that this would make the compost neutral, the wood ash would change the pH of the compost, but good research indicated that compost is very near neutral when finished and does not need help. The very caustic nature of that wood ash could kill off the bacteria needed to digest your compost.
Why some people state that adding cooked vegetables to compost is not a good thing is unknown because I have done just that for many years with no problems. If you can eat tht material you can compost it, and there is also a whole lot of stuff you cannot, or maybe would not, eat that can be composted.

Kimmsr, what you said about cooked vegetables makes sense, I really see no problem with mashed potato in compost. I mean, bones, keratinous matter etc. is forbidden for reason, but this...

Thanks.

Anything that was once alive can be composted. I composted my dog several years ago. I don't recommend that for beginners, but it is done routinely on large scale by professionals.

Compost is applied to lawns at a rate of 1 cubic yard per 1,000 square feet. A cubic yard weighs about 750 pounds. If the compost was 1-1-1, and if that was readily available like synthetic fertilizer is, the compost would apply 7.5 pounds of N, P, and K to the 1,000 square feet. So compost is a fertilizer. It is just used at much higher quantities, and over a longer time frame, to get the value out of it.

Is a dog a "green" or a "brown?"

What's the trade name of a professional large-scale dog-composter? And would a small-scale dog-composter only handle chihuahuas and toy poodles?

Fats cause digestion problems for the bacteria that work on your compost and that slows them down and that is why many people do not add fats to the compost. In small quantities fats should not be a problem, but what is a small quanity depends on the volume of compost. A cup of fat in a garbage can composter will be problematic while the same amount in a 4 x 4 x 4 compost pile will hardly cause the bacteria to blink.
Bones are very dense and can take years for the bacteria in a compost pile to digest. Bones are more difficult then wood is to compost. Bones go into my compost and usually when that mix is pulled to use the bones are sorted out and run through the shredder. People have been putting bone meal into their compost, and soil, for years, but that is ground up bones not whole ones. There is no real problmne with composting bones either, just be aware they may stay around for several years in the form you put them into the compost.

I'm a little leery of tossing chicken bones through my Harbor Freight electric shredder. I'd think I'd be going through blades quickly grinding bones in it.

I guess I can wait for a few passes through hot composting batches till they disappear.

Serious reply to whimsical question:
Dogs, being high in protein, are very green.

Garden-Ville, in San Antonio, composts dead livestock and road kill deer, etc. routinely. They probably get 2 per week. After 4 days in a hot pile, there is no trace of them. Bones, hooves, and skin are all gone.

Try putting a raw chicken into a 150 degree oven for 4 days and see what you have left. Roadkill animals still have the gut bacteria to help decompose from the inside out.

If your shredder is a hammermill type bones can be processed but if it has blades, or is a string type, bones will not get chopped up.

Composted vegetation is mostly used to improve soil texture and aeration. Same for peat moss which has less nutrition. Peat moss plus a chemical fertilizer can almost always replace compost.

Wow, dchall. That's both facinating and disgusting at the same time. I had no idea anyone did this on a commercial scale. What kind of compost does that make then? How do they sell it?

It's absolutely amazing that an animal that size can be consumed that quickly.

Kim

From what I understand Garden-Ville's feed stuffs include horse manure (adjacent to a race track), restaurant trash, expired grocery store veggies, expired and non compliant soft drink syrup, excess dairy cream, and shredded mesquite and juniper. They make 400,000 cubic yards per year so 100 cubic yards of animals are a very small part of it.