In the spring and summer a large amount of store space is dedicated to selling chemical fertilizer, well rotted manure and compost. An understanding of fertilizer is needed to make the correct one for your garden
Chemical fertilizer is available in granules, liquid, powder and sticks. Each of these are also available in different formulations. Understanding differences between various fertilizers takes the guess work out of the purchase and application.
Fertilizer formulas are located on the outside of each fertilizer container. They consist of 3 numbers with a dash in between. Each number represents the percentage of the nutrient contained in the fertilizer. A common formula, 20-20-20 contains 60 percent nutrients and 40 percent filler. The formula 10-10-10 contains 30 percent nutrients and 70 percent filler. Higher numbers mean less product is needed to fertilize the same area.
The first number in the formula represents the percentage of Nitrogen (N) in the package. Nitrogen encourages the growth of foliage and stems as well as enhances the roots ability to take up nutrients.
When plants are deficient in nitrogen their leaves start to loose the dark green color. If the deficiency continues the leaves will turn light green with the older or bottom leaves dying.
Excess nitrogen will produce weak top growth; long stems and huge leaves. Flowers, fruit and seeds will be delayed.
The second number Phosphorus (P) is needed to make plants cells divide and the plant to grow. Phosphorus is also needed to promote flower and seed development insuring the plant is ready to hibernate and survive the cold winter.
Plants that are short in phosphorus usually have a weak root system and stunted growth. A purple leaf discoloration is also a common symptom.
The last number Potassium (K) also benefits fruit production and insures the plant is dormant in the fall.
Leaves on a plant that is short of potassium usually have yellow edges that will eventually turn brown. Look for weak stems and poor root development.
Fertilizer packages may also list a number of other trace elements that could include: calcium, magnesium, sulfur, iron and manganese. Trace elements balance the formula but are not needed in large quantities.
Fertilizer application depends on the composition of the fertilizer. Fertilizer that is water soluble, a liquid or powder, are easily dissolved in water. They can be applied with a watering can or a garden hose.
Plant spikes are solid masses of fertilizer and filler that are pounded into the ground or placed in pots near the roots of the plants. Water from a hose or rain will slowly dissolve the stick, releasing fertilizer for the plants use over a period of time. The amount of fertilizer released is regulated by the moisture level in the soil.
Granular fertilizer comes in quick or slow release. Quick release dissolves quickly and often needs a second or third application in a season. Slow release is usually more expensive and is available to the plant for a longer period of time. Using a mechanical spreader helps insure that granular fertilizer is spread uniformly.
Natural fertilizer, bone meal, fish fertilizer, manure and compost have a lower percentage of active ingredients than chemical fertilizers. These fertilizers break down quickly and are easy for the plants to access. Compost and manures are bulky but they improve the soil structure.
Using this information decide what type of fertilizer works for the garden before entering the fertilizer isle. It will make the trips quicker and less frustrating.
For best results, always read the package and follow the manufactures directions.
Linda Tomlinson is a horticulturalist that lives near Rocky Mountain House. She can be reached at www.igardencanada.com or your_garden@hotmail.com