Container Gardening by Emmanuel Mwesige - HTML preview

FERTILIZER AMENDMENTS

Add fertilizer and lime when preparing a potting mixture for containers. The fertilizer adds nutrients that are essential for plant growth. Lime supplies the essential elements calcium and magnesium.

It also adjusts the soil to a pH range suitable for optimum plant growth (sweetens the soil).

Choose a premium grade of fertilizer to add to the potting mixture, one which contains both major and minor elements needed for plant growth. This information is listed on the fertilizer bag. An analysis such as 5-10-15, 5-10-10 or 6-12-12 is satisfactory. Add fertilizer to the mixture at the rate of 2 kilograms per cubic yard (27 cubic feet) of the potting mixture.

Mixing a potting mixture properly is important. All ingredients must be blended sufficiently to make a homogeneous mixture. Layering of amendments due to improper mixing can interfere with root growth and causes poor quality plants.

Because most recommendations for potting mixtures are given on a cubic yard/cubic foot basis, it is easier to mix on this basis. Smaller volumes from 1 to 5 cubic feet are easily mixed in a wheelbarrow. The cubic foot volumes are usually printed on the wheelbarrow. Small wheelbarrows hold approximately 2 cubic feet; medium size wheelbarrows hold 4.5 cubic feet, and the larger construction type wheelbarrows hold 5 to 5½ cubic feet. Add the ingredients, including fertilizer and lime, to the wheelbarrow on a volume basis and turn them several times to blend them. Remembering that a standard bushel basket holds 1.25 cubic feet, this means of measuring can also be used.

A gardener can mix a large volume of a potting mixture on a driveway or in a garden area. Add the basic ingredients to form a pile. Distinct layers form as ingredients are added. Simply sprinkle fertilizer and lime on top of the pile. Turning the pile three times is sufficient to blend the ingredients properly. The best method is to start a new pile of the mixture each time the original pile is turned. This method reduces any layering effect.

Here are a few recommendations that, when followed, will give you a better potting mixture.

1. Expose peat moss or bark to rain for several weeks before using. Both are difficult to wet and require repeated soaking.
2. Avoid over-fertilization. This can cause root damage.
3. Cover potting mixtures with plastic cloth to keep the unused mixture freer of weed seed.
4. Place potting mixture in full sun, cover with clear plastic, and seal down the sides during high temperature periods to kill weed seeds and harmful fungi. Soil should be no more than a foot deep to ensure sufficiently high temperature at the bottom of the pile. This process may require several days for a beneficial heat build-up.