Growing Blueberries
Site and Soil
Blueberries require full sun and a well-drained soil. They prefer a gravelly or sandy soil and will not thrive in heavy soils, particularly if they are damp. Their roots are very fine and cannot penetrate clays easily. Damp soils are one of the primary reasons for failure with blueberries, so although watering is important after transplanting, soggy ground is the kiss of death for blueberries.
Be sure that you add organic matter such as leaf mold or dampened peat moss to the soil if your land is lacking. Mix any organic matter well into the soil, particularly if you use peat moss. Never use more than 25% organic matter in the soil. A common cause of death is planting in a hole filled with materials such as peat moss. This will draw water away from the roots and, when wet, will stay soggy. Mixing well is the key.
Blueberries need an acidic soil to thrive. If you do not know the acidity level (pH) of your soil, have it tested at your Dept. of Agriculture or purchase a pH kit to test yourself. A pH of 4.5-5.5 is ideal for blueberries. In high pH soils the leaves will yellow, a condition known as chlorosis. In such situations use a source of iron such as iron chelate. Follow the directions and water it with the solution. It does not take much, but the difference it makes is often dramatic. Do not use aluminum sulfate as this material can be toxic to plants. If your soil’s pH is over 5.5 you can add a small amount of wettable sulfur to the surface.
Planting
Blueberries are shallow rooted plants. When planting, place the root ball at the same depth as in the pot. If you have a bare rooted plant, place the roots just barely under the surface. Be sure to water well after transplanting and water with approximately 2-3cm (1 in.) of water per week if it does not rain. Do not keep the ground soggy.
It is advisable to use a 3cm layer of mulch such as decomposed bark, pine needles or sawdust on the surface. Remember that fresh materials like sawdust or new bark will use available nitrogen as they break down. If you must use fresh materials, add a dusting of blood meal to the surface before mulching. This will provide a source of nitrogen. Bone meal and compost are not advised as these raise the pH of the soil.
After Care
Blueberries need little pruning in their early years. Later you can remove crossed limbs or older stems to let new canes rejuvenate the bush. Each year a dusting of blood meal, cottonseed meal or linseed meal will provide adequate nutrients. Keep competing weeds away with annual mulching. Be sure not to cultivate deeply or the shallow roots will be damaged.