Gardeners are always on the lookout for a good load of compost, aka black gold. They refer to it with reverence because of its ability to transform even the hardest, poorest soil into something workable that can support plant life. Some gardeners have their favorites, like old, rotten cow manure or the newer, trendier cotton burr compost. Which compost is the best? An argument could be made for any.

Compost is sometimes confused with manure, soil, or mulch. Simply put, compost is the completely broken down form of plant and animal material. It may closely resemble soil, but is almost always dark brown to black and has a crumbly consistency. The original material — be it yard waste, manure, food scraps, etc. — is beyond recognition.

Compost is made by piling materials or collecting them in bins to allow heat and microorganisms to break them down.

Since there is little difference in compost (once that plant or animal material is completely broken down), the best kind is probably the free or cheap kind.

You can make compost yourself by collecting yard waste, food scraps, etc., and piling it or placing it in a specialized bin. If making your own is not your style or you need it now, your options are local farmers (probably only if you know one), the City of Lawrence or local garden centers.

The City of Lawrence collects yard waste and composts it with commercial equipment to produce a safe finished product. The big annual sale is March 23, 24 and 25, from 8 a.m. to 3 p.m. at 1420 E. 11th St. Self-loaded containers are free. A scoop from the big loader (to fill a standard pickup) is $10. This year they are also opening the facility every Saturday from now through mid-December for self-load and will also load vehicles ($10 scoops) on the first Saturday of each month.

Some garden centers offer bulk compost that can be loaded into a truck or delivered for a fee. Vinland Valley Nursery and Pine Family Landscape Center have offered bulk compost in the past (call for current availability) .

Most garden centers offer an assortment of bagged composts. As mentioned, cotton burr compost is a favorite of many gardeners, along with chicken poo, cow/steer manure and others. These products have been managed to produce a consistent, stable, safe compost.

Mushroom compost is one commercial compost product to use with caution. It is made from the leftover plant material associated with mushroom production. Mushroom compost can vary considerably depending on the material used and the mushrooms that were grown on it, but it is often high in soluble salts. Repeated or heavy use of compost with high salt content could allow salts to build up in the soil (bad for plants).

If you are fortunate enough to get materials from a farmer, be sure the material is fully composted before using. Partially composted materials (from any source) may tie up nitrogen in the soil as they complete the breakdown process or may contain higher amounts of nitrogen that can burn certain plants. They are also more likely to contain weed seeds and other unwanted remainders of the source material. Horse manure is especially prone to containing weed seeds since horses do not digest the seeds.

Compost benefits soil by improving water movement, making it easier for plant roots to penetrate the soil, reducing water runoff, making nutrients more available to plants, and improving the overall growing environment.