Guide to Buying Bagged Compost

Gardeners know compost is good stuff. Made of decomposed organic material, compost improves the soil and helps plants grow. While many gardeners make their own compost, they sometimes need more compost that they can make--or they need compost in a hurry. That's when bagged compost is a great option.

Types of Bagged Compost

Bagged compost may be made of all types of organic matter, including manure, grass clippings, leaves, worm castings and even mushroom compost. Some of the most common include:

Yard waste compost, made from grass clippings, leaves and other plant materials, is excellent for adding organic matter to the soil, improving aeration and increasing water absorption.

Manure compost, usually made from horse, cow or chicken manure, may have other ingredients, like sawdust or straw mixed with it. It often has more nutrients than yard waste compost.

Worm castings compost (vermicompost) is produced from worms feeding on manure and other organic wastes. Often mixed with soil, it can be high in nutrients, so care must be taken when using it.

Knowing Which Bagged Compost to Buy

Many gardeners make their own compost at home. Not only is it a great way to keep wastes out of landfills, it also supplies them with compost they can use in their gardens. Many compost supplies are available for gardeners who want to compost at home. While composting at home offers the advantage of knowing exactly what is in your compost, the disadvantage is that you may not have compost when you need it.

Steps

When selecting bagged compost to buy, just follow these steps to determine the best bagged compost for your gardening needs.

1. Determine how you want to use your compost. Many gardeners, especially those with clay soil, use compost to improve soil drainage and increase organic matter in the soil. Some also use compost as a mulch. Other gardeners may use compost to add organic matter and nutrients to the soil.
2. Read product labels. The better bags of compost list the ingredients in the compost.
3. Feel and smell the compost. The best compost is crumbly with a rich, earthy smell. Compost should be not wet and heavy.

Tips

Here are some tips for buying bagged compost.

• Pay attention to ingredients in compost, as the ingredients change your soil composition. For instance, manures can add more nutrients to the soil. If seafood shells are in the mix, the soil may become more toxic to nematodes.
• Buy a couple of different types of bagged compost. This can help you see the differences in the mixes. Some gardeners mix different types together.
• Conduct some home tests to determine if it's good or bad compost. Ideally, compost should be free of weed seed and herbicides.

Best Bagged Compost

Brands of bagged compost may be available regionally or nationally. Some of the best bagged compost that are available in several places throughout the United States include:

"Gardener's Gold" from Garden's Alive

Tested as an effective soil amendment and a Seal of Testing Assurance recipient, Gardener's Gold is produced with leaves, brush and grass and composted for a minimum of two years. It contains no animal wastes, sludge or industrial wastes. It can be used as a mulch, soil amendment and nutrient supplement. Gardener's Gold improves soil structure and aeration, increases water absorption and reduces nutrient run-off.

Coast of Maine Compost

Coast of Maine offers several bagged compost options, including composted cow manure blended with peat moss, and a blend of lobster shells, compost and peat moss.
Both are designed to improve and revitalize soil.

Leafgro Compost

Made of composted leaves and grass clippings, Leafgro is a good soil conditioner, especially when mixed into the soil before planting shrubs and trees.

Expert Advice

Question. Mike: Do you happen to know if it's possible to buy good quality compost in bags? I'd like to use compost in my garden, but only seem to be able to find manure and topsoil in bags at the garden center. I've seen places that will deliver loose compost by the cubic yard, but I don't have a driveway for them to dump it. Love your show!

---Peter in Ardmore, PA

Answer. Thanks, Peter! Now if you have access to good quality yard-waste compost in bulk, my first suggestion is to see if it can be delivered to a friend's home nearby or some other mutually agreeable site where several gardeners could share both it and the cost. You'll find lots of info on buying bulk compost in this previous Question of the Week.

Otherwise, the basic answer is yes; there are high quality bagged composts out there. But as with most things gardening, the devil—or angel—is in the details. Here's an updated version of how I addressed this topic in my 2006 book, "Mike McGrath's Book of Compost" (still in print, kids; get your copy today!)

If we're talking about the cheap, wet, heavy, generically bagged stuff without a lot on info on the label sitting out baking in the sun at a big box store, it's not my first choice. (Or second, or third, or…) It shouldn't be anyone's choice, really. The labels and names on cheap bags of "Maybe Compost" are generally somewhere between non-existent, confusing and extremely misleading (as the materials inside the bag often are as well). And this low-rent spread has probably been anaerobic inside that bag for a long time.

If it's all you can find (and it isn't; there's always mail order if you truly live in a horticultural supply desert), two esteemed experts I interviewed for the book, Ohio State University Professor Dr. Dan Herms and University of Maryland Professor Emeritus Dr. Frank Gouin suggest you buy a sample bag, take it home, open it up and give the contents a 'quack' test. (If it looks like good compost, feels like good compost and smells like good compost, it might actually be good compost.)

If it quacks loud enough, go back and get some more, empty the bags out, mix the contents together (ideally with some REAL home made compost or some of the premium stuff we'll soon mention) and let it sit awhile before you use it.

"Square Foot Garden" author Mel Bartholomew once offered a variation on this method during one of our conversations. He suggested you visit a number of different stores, buy one each of their bagged composts, bring them home and evaluate them. Then go back and buy a couple bags each of the best ones and mix them together—again, ideally with some backyard compost or stuff from a premium bag.