Flowers get what they need to grow from soil. The texture and pH level of soil affect the availability of nutrients that your flowers can use as well as movement of water and air. The amount of each nutrient flowers need depends on the type of flower and the results you wish to obtain. As nutrients are used up in soil, they must be replenished. Soil fertility and plant productivity result from organic matter content in the soil. Increasing organic matter in soil improves soil structure and increases biological activity, resulting in better plant yields.
To learn your soil's pH, have your soil tested. You can test your soil with a home testing kit or you can take a sample to your local, county or state agricultural agency. If your county extension service does the testing, someone there will usually send recommendations for fertilizer and soil amendments with your results. Most flowers like a soil acidity that falls in midrange, about 7.0.
Sandy soils do not retain moisture and leach out important nutrients that flowers need. Soils with a high clay content retain too much moisture, giving flowers soggy feet. Wet clay soil can cause damping off and rot, and it dries into a hard-baked crust. The ideal soil is garden loam with about equal parts sand, clay, and humus, which provides nutrients for beneficial micro-organisms in the soil. Organic matter or compost can be added when the soil is turned, which also increases the oxygen content and increases microbial activity.
There are three main nutrients that flowers get from soil: nitrogen, phosphorous and potassium. Nitrogen promotes leaf growth and increases seeds and fruits. Phosphorous promotes rapid growth, particularly in blooms and root systems. Potassium is absorbed in larger amounts than any other nutrient except nitrogen, and helps in building protein, aides the photosynthesis process and helps to fight disease, producing strong, healthy plants. In addition, there are secondary nutrients and micronutrients that also are obtained from the soil plants grow in.
Identifying Nutrient Deficiencies
An imbalance of nutrients can stunt flower growth, produce weak plants or cause them to die. Examine the flowers themselves to determine which nutrients plants are lacking. General plant weakness and older leaves that turn yellow, red or purple indicate a nitrogen deficiency; purplish or bronze colored leaves indicate a phosphorous deficiency; and leaves with yellow, translucent spots and browning edges indicate a lack of potassium.
Using the proper soil additives can correct nutritional imbalances and promote healthy growth. Good sources of nitrogen are bat guano, blood meal, fish meal and soybean meal. Phosphorous can be obtained through the addition of bone meal, colloidal phosphorous and rock phosphate. Granite dust, greensand and ground kelp are all good sources of potassium.
Plants get the three main nutrients from decaying plant matter. Compost is a good all around additive and one way to imitate nature and provide your flowers with all of the nutrients they need. Compost also adds humus to the soil, which improves soil texture.