Frequently Asked Questions

Doyle’s Thornless Blackberry® Frequently Asked Questions How far apart should the plants be? We recommend 8 foot in the row and 6 foot between rows or 3 foot wider than equipment. When is the best time to plant the blackberries? We recommend any time from the last freeze in the spring to about two weeks before the first freeze in the fall. What is the best type of structure to support the plants? On a mature plant you will get 5 canes that will grow up to 40 foot long each. The support is needed so you can keep the fruit at a height that makes picking easy. Generally a grape type trellis is best with 12 gage wire at 3 and 6 foot with others in-between. Tie the primary canes along the bottom wire using binder twine or the new berry klips sell. The plastic klips can easily be reused and last several seasons. With the primary along the bottom, the laterals should grow up towards the sun. Arrange them so they get as much sun as possible tying them the same as the primaries. When the laterals get to the top cut about 2 inches off the tip. New canes growing for next years crop should be attached the same way but on the opposite side of the wires so it will be easy to remove the dead canes after they have fruited. How large are the berries? Generally the fruit will be one to one and a half inch long. Letting the fruit fully ripen will greatly add to the length. How sweet is the berry? If allowed to fully ripen, it is very sweet. According to a winery, the sugar was 11% compared to about 6% for wild blackberries. If it is “picked’ instead of let fall into your hand, it will not be sweet and pucker your mouth like a lemon. How does the taste compare to other blackberries? This depends on your taste preferences but generally since it is sweet, the taste is pleasing to most people. Do I need to protect the plant from our extreme winters? Our winters in Indiana get down to as low as 10 below Fahrenheit and as high as 105 in summers. Pretty extreme. We have not done anything to protect the plants and they have survived over 30 years. In colder areas with temperatures below minus 20, it necessary to provide some protection. Snow is first choice, then high tunnel or 6 mil white or clear plastic temporary greenhouse is all that is needed and it will extend the growing season also. How and when do I prune the plants? We have never pruned the plants but let the canes grow to full length. Tipping the primaries at any length will cause the laterals to grow longer but total plant and fruit production should be the same. After the plant has fruited, the two year old canes will die and need to be removed back to the ground to get rid of clutter and let more sunshine get to the new canes. This can be done two months or more after fruiting ends but generally there are less errors in cutting in the spring. The plant recovers nitrogen from the dying canes and stores it to use in the spring to get the plant started growing again. How long does the plant live? We don’t know. We have plants over 30 years old still producing. Generally at about 15 years old the production declined but we don’t know if this was from age or shortage of fertilizer as they had never been fertilized after the year of planting. Two customers have reported their plants are over 40 years old. What should the soil PH be? Generally a PH of 5 to 6.5 is best. What type of soil is best? Sandy loam is best for all brambles as the loam retains moisture and fertilizers while the sand lets excess water escape. Other soils work find as long as you provide good drainage. What fertilizer is best? Our organic customers recommended using either Speedy-Gro 100% Kelp or Neptune’s Harvest Fish and Fish/Seaweed. With either, a weekly application as a foliar spray yielded 2-3 gallons of fruit in the second summer. We also recommend Doyle’s Organic Blackberry Fertilizer 4-4-4 with nitrogen at planting and three weeks after flowering starts. Use 4 ounces of Doyle’s 10–0-0 high nitrogen fertilizer when planted and annually in September. Can I use compost or manure? Yes, you can but the first rule in using compost or manure is that if you can still tell where it came from its not ready. Second, its best to mix with the soil to avoid any hot spots or excesses. Finally, no compost or manure is balanced so its important to get soil tested for each crop so you can balance the fertilizers and minerals. How close can I plant to wild brambles? The further the better especially raspberries. Six hundred feet is the recommended minimum. The reason is to avoid transmission of virus or disease and raspberries are very susceptible and become incubators. If you can keep the other brambles healthy then there is no real problem Cross pollination with blackberries is possible but the affects may be good as well as bad. How much sun do they require? The plants want all the sun they can get but 6 hours is minimum. Shade may reduce the production. How should I plant them? Just keep in mind that you will need good drainage, everything else is secondary. Tilling the full row where you are planting is better than digging a hole since it will offer better drainage. If your soil is poor then digging a 12-15 inch hole in the loose soil and mixing in compost, manure and/or potting soil and even sand will get good soil for growing brambles. Adding a balanced fertilizer such as 10-10-10 by spreading 3-4 ounces in an area of about 12 inches around the plant at the time of planting and again after harvest. Use of foliar spray on a weekly basis is also recommended. Do the plants require irrigation? Any plant will benefit from a steady and regular watering. A drip irrigation system is the best since it will not waste a lot of water and is an easy way to fertilize the roots. The plants need about an inch of water which is a little over one half gallon per week. If you use plastic then you would only need a quart per plant per week. Double this when berries are producing. Should I put mulch around the blackberries? Mulching reduces watering frequency and aids in control of weeds. Good mulch include pine straw, wood chips and seed free grain mulches such as wheat or rye. We prefer and recommend using 10 mill plastic on all gardens. Does plastic help? Yes, we have 10 mill plastic on all plants. This weight of plastic will last for many years and in the long run is less expensive than thinner plastic that has to be replaced every few years. We recommend covering the entire garden with the plastic and then cutting small holes for the crops to be grown. This was a process that Thomas E Doyle developed in the late 1950's and he sold the plastic until his mid 90's. It is now available from Ron and Susan Pletcher, 66786 County Road 17, Goshen, Indiana 46526, 574-831-2329. Plastic provides moisture due to condensation on the bottom side, keeps weeds down and raises the heat of the soil. Are there other plants that should be kept away from blackberries? Yes, tomatoes, potatoes, eggplant and peppers are susceptible to the same diseases as blackberries. These diseases can remain in the soil for up to three years after the last planting.