Hot Compost Vs. Cold Compost
Compost basically falls into two rough categories, "hot" and "cold." Each has its advantages and disadvantages.
By Veronica Lorson Fowler
The Iowa Gardener
There's an old saying that the three best things you can do for your plants is compost, compost, and compost.
And compost can indeed to wonderful things for your garden: It supplies nutrients for plants, breaks up clay, makes sandy soil hold water better, attracts beneficial earthworms, stimulates biological activity in the soil, and provides micronutrients.
Granted, there is mushroom compost, composted horse manure, composted chicken manure, composted "sludge" (human waste!), and other types, but those have mainly to do with the material that was composted, not the type of compost method itself.
This made with the so-called lazy method. The main benefit of this method is that it's very little work. Pile up materials (or put them into a big hole dug in the ground) and let them break down for a year or two with an occasional turn if possible. To use, pull off non-decomposed materials off the top to get to the "black gold" underneath. Cold compost can contain active weed seeds, so it's best used in the bottom of planting holes to prevent weed problems.
Hot compost comes from a compost pile constructed with a balance of nitrogen-rich and carbon-rich materials that are turned regularly, at least every couple of weeks.
When skillfully done, hot compost can reach a temperature of more than 130 degrees Fahrenheit, so hot it's uncomfortable to put your hand in the center of the pile and hot enough to kill many disease pathogens lurking in the garden as well as weed and other seeds. Use on the top surface of the soil.
The advantages are clear, but making this type of compost takes a bit of skill and monitoring. Some even use compost pile thermometers to make sure they pile reaches optimum high temperatures.
Nearly any type of bagged, commercial compost is "hot" compost. Most municipal compost is also the hot type, but do ask. Methods vary from city to city. Just ask the Kansas City homeowners a couple of decades ago who purchased composted sludge from the city. People spread it all over their lawns and were amused and appalled when hundreds of tiny tomato plants sprang up all over.
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