Get Your Dirt Right

     The most important elements in your soil for plant growth are nitrogen, phosphorous and potassium. They are the N-P-K you see on fertilizer bags. Plants also require micro­nutrients such as calcium, sulfur, magnesium, iron, zinc, copper and boron. 

     Building or improving your soil is extremely important for plant health. The foundation of soil is weathered rock. The best way to build up your soil, after determining what it is missing, is to use natural rock powders.

     When I start a new garden, I like to use ground rock phosphate to increase phosphorous levels, if necessary. This enables phosphorous to be released slowly over many years. Adding greensand mined from petrified seaweed deposits, also known as glauconite, increases potassium levels. In addition to potassium, greensand also contains a variety of trace elements known as micronutrients. They are only needed in small amounts for plant health.

     To determine what your soil needs, you need a soil test. (See the University of Maryland Cooperative Center’s instructions:

     With test results in hand, you will want to adjust your pH between 6.0 and 6.5 for vegetable gardening. Using dolomitic lime also adds magnesium in addition to calcium. It takes five pounds of lime per 100 square feet to raise the pH one point. A soil test will tell you how much to use. You can lower the pH by adding sulfur.

      In addition to compost, the organic nitrogen I like to use in vegetable gardens is alfalfa meal or pellets. Alfalfa is a deep-rooted forage crop commonly fed to livestock. The fertilizer is made from alfalfa that is heat-dried after harvest to preserve its nutrients. It makes a nice organic, high-nitrogen fertilizer that is especially helpful for green, leafy crops. Any feed store should stock alfalfa fertilizer.

     Other organic fertilizers include fish meal, fish emulsion, dried blood, soybean meal, seaweed, bone meal and cottonseed meal. Manures, generally from animals that are strictly herbivores, should always be composted. Poultry and rabbit manure are two of my favorite manures for the compost pile.


Learn to grow a vegetable garden step by step in my eight-session class,  Vegetable Gardening 101, part of AACC’s continuing education program, April 2 to July 23, 6:30-7:30pm, Beaver Creek Cottage Gardens, Severn, $92, rsvp: 410-777-2325.


Maria Price founded Willow Oak Herb and Flower Farm and is now proprietor of Beaver Creek Cottage Gardens, a small native and medicinal plant farm.