Help with struggling blueberries

Asked July 22, 2018, 8:23 AM EDT

My blueberry plants are just not thriving. The first two I have pictured did produce maybe a quart of berries combined but they are at least 4 years old so Id expect them to produce more. Any suggestions as to the problem wpuld be appreciated. But also, when is the best time to fertilize or try to raise the soil pH of blueberries? Thank you! April

Ingham County Michigan

2 Responses

It looks to me that the soil pH is too high for blueberries. Blueberries prefer a soil pH from 4.5 to 5.5 and it looks like yours is 6 or above. There are no quick ways to change soil pH. Lime is used to raise the pH and sulfur or sulfates are used to lower it.
I recommend that people test their soil pH before planting blueberries and if it is 6 or above bring in new soil or mix peat moss with the soil in the planting hole to lower the soil pH. Do not mix compost or manure in the planting hole as these will raise the soil pH.
I suggest you replant the blueberries and correct the soil problems you have. Dig a new hole about 2 feet wide and a foot deep. Buy a bag/bale of peat moss from a garden store and mix the soil with the peat moss when you replant the plants. Shake off as much of the old soil as you can and cut off all the short spindly shoots to reduce the leaf area and reduce the transplant shock. You may want to add a little sulfur in the mix as you plant. DO NOT use a lot of sulfur. A half ounce should be enough. Mulch the plants with wood chips or bark mulch. Be sure to water them in really well.
Blueberries only use ammonium nitrogen and cannot use the nitrate which most plants prefer. Use a fertilizer for acid loving plants such as Miracid or some other mix for rhododendrons and azaleas. I normally do not recommend fertilizing after the 4th of July since I want shoot growth to stop and set fruit buds but in your case fertilize after you replant.
You really want to grow a good sized bush for a few years so I suggest you remove all the blossoms the first few years and concentrate on growing a new bush and not picking a few berries. Cut off all the soft spindly shoots from the base what you want is strong shoots coming from the base of the plant.

Thank you so much! This information is very helpful!