GROWING BLUEBERRIES Quick Links Before You Start Soil pH Planting Irrigation Fertilization Weed Control/Mulching Pruning Troubleshooting Quick BEFORE YOU START Blueberries must have a soil pH between 4.5 and 4.8. Have your soil tested. If the pH level is outside the specified range, begin amending it right away. Excessive amounts of sulfur can be toxic to your plants. SOIL PH The term pH refers to the acidity or alkalinity of soil. The pH level is important to know because it affects a plant’s ability to obtain nutrients from the soil and each type of plant has different soil pH requirements. Soil pH should be between 4.5–4.8 for blueberry plants. A pH of 5.0 is too high! HOW TO AMEND YOUR SOIL FOR THE HEALTHIEST, MOST PRODUCTIVE BLUEBERRY PLANTS Amendments like sawdust, aged wood chips, old leaves, or finished compost can provide minimal pH changes but generally do not last long. Sulfur is the most effective method for lowering soil pH but a combination of the above materials can give adequate results. The amount of sulfur to be incorporated varies according to the soil type [sand (light), loam (medium), and clay (heavy)], as well as the present pH level of your soil. Tip: Addition of sulfur is often necessary to adjust the pH. Elemental sulfur is the best material to use to reduce pH. Amend soil with sulfur, not ammonium sulfate or aluminum sulfate. You can consult your local cooperative extension service for advice on how to test your soil. Caution: Excess sulfur, resulting in a pH that is too low can be toxic! Do a soil test and apply the proper amount of sulfur. Do not guess. PLANTING Wood chips can be mixed into the soil prior to planting. Wood chips aerate the soil, increasing drainage and root penetration. This method is good for all types of soil, but most beneficial in heavier, silt loam or clay soils. Put a two-to-three-inch (2–3") deep layer of wood chips over your planting row and incorporate it thoroughly into the top six to eight inches (8") of soil. Then you’re ready to plant. If you use peat moss, thoroughly mix forty percent (40%) peat with sixty percent (60%) soil making sure the peat is thoroughly saturated with water before mixing. Place this mixture under and around each plant. Make sure the peat/soil mix is thoroughly covered with one-half to one inch (½–1") of plain soil after backfilling the hole. This practice is to benefit the first 60–90 days of root development for strong plant establishment. Any peat not covered with soil will quickly wick moisture away from the plant and cause roots to dry out rapidly. WARNING: Shavings or sawdust with manure have too much nitrogen for first-year plants. IRRIGATION Because of a very shallow, fibrous root system, frequent, short-duration watering is required. Maintain moisture, and do not allow roots to dry out. Water one to three (1–3) times per week, not every day. Drip irrigation placed between the mulch later is the healthiest and most effective method. Water is applied directly to the root zone where it is needed, while keeping moisture off the plants, thereby reducing disease pressure. Blueberry plants cannot efficiently draw nutrients from the soil if the pH is not within a certain range. This leads to stressed or malnourished plants which will not produce the best crops possible and will be more susceptible to problems. For long-term, optimum success, measure pH levels every year or two and amend as needed. FERTILIZATION First year: To avoid burning the roots, wait four to six (4–6) weeks after planting before fertilizing, however, do not fertilize after July 1. Apply one ounce (1 oz.) of ammonium sulfate in a circular band around each plant. Subsequent years: Apply two ounces (2 oz.) per plant at bloom time and again one (1) month later. Do not apply fertilizer after July 1. Late-season fertilizing could lead to new, tender growth which is susceptible to winter injury and may lead to entry points for disease. WEED CONTROL/MULCHING Maintain a three to four-inch (3–4") layer of aged wood chips as mulch to support water retention. Avoid treated or colored wood chips or mulch. Do not use Cedar or Black Walnut chips. Also avoid using leaves or an excessive amount of sawdust, as both can mat down and prevent moisture from reaching the plant's roots. Regular, manual weeding will be necessary. We highly recommend using drip irrigation under the mulch. PRUNING Remove all flowers during the first two to three (2–3) years. Do not allow berries to develop. No pruning is needed during the first three (3) years, unless you discover broken, damaged, or diseased branches. After the first three (3) years, blueberries should be pruned annually during the dormant period. Your goal is to have approximately twelve (12) canes per plant. Older, heavy branches in the center should be removed to improve air circulation and light penetration. REmove lower, weak, and damaged branches and branches less than six (6) incesh long. These branches will never fruit and can serve as an entrance point for disease. New wood produces the largest fruit. Canes should be a mix of one to three (1–3) year old canes and any canes over two inches (2") in diameter should be removed. TROUBLESHOOTING Yellow leaves on blueberries can be quickly corrected with a foliar application of one tablespoon chelated iron per gallon of water sprayed over the leaves. You should see greener leaves in a few days. Often, the underlying problem is that the soil pH is too high. Have your soil tested and make the required amendments. You should see twelve to eighteen inches (12–18") of new growth each year. If not, check your soil pH and/or use a little more fertilizer. Be sure your plants are receiving enough water, especially during dry spells. BLUEBERRIES QUICK REFERENCE Spacing Four to five feet (4–5') between plants. Eight to twelve feet (8–12') between rows. Be careful not to plant too deeply. Irrigation Keep soil moist throughout the establishment period. pH Requirements For best results, amend pH levels before planting, however, plants can be successfully established without prior pH adjustments if you follow our instructions. Measure/maintain pH levels regularly for best success. Adding sulfur may be necessary to adjust pH: 4.5–4.8 this is very important. Fertilization Wait four to six (4–6) weeks after planting before fertilizing to avoid burning roots. Year One: one (1) ounce of ammonium sulfate in a circular band around each plant. Following years: two (2) ounces per plant at bloom time and again one (1) month later. Don't fertilize after July. Avoid fertilizers containing potassium chloride. Weed Control Mulch with three to four inches (3–4") of wood chips. Avoid treated or colored bark mulch. Regular manual wedding is necessary. Special Considerations For best production, at least two blueberry varieties should be used for cross-pollination.
