What type of irrigation system works best with blueberries?

Question

Several months ago I planted a row of blueberries in order to form an (edible) hedge. At the same time I installed an automatic watering system for these and the rest of my fruit trees and vegetable patches.

I used a variety of systems including mini sprinklers, drippers and soaker hoses for the different types of trees, shrubs and vegies. For the blueberries, I put in two drippers for each plant, one either side of the trunk about 20cm (8 inches) from the trunk and underneath a 1-2 inch layer of lucern mulch. The rationale for this was that since I will train these bushes to grow as a hedge, a dripper would work to sit under the hedge and apply water to the root zone, whereas a sprinkler would get blocked. I applied well rotted compost and acid loving plant poultry manure based pelleted fertiliser when planting, and added additional fertiliser 2 months after planting. The subsurface soil in my area is an acidic heavy clay, although the top 6-12 inches in the location of the blueberries is a more balanced imported garden soil. I am in Sydney, so we are currently in the middle of a hot, dry summer.

That is the background. My problem is that the blueberries are growing very slowly with little new growth and the tips (in some cases the 'tip' is up to half of the leaf) are showing a burnt reddish appearance and shrivel up and die. I found this question which appears to describe the same issue. One thing I noted is the suggestion to wet the entire root area. I also found on this site the comment

There is little lateral translocation of water and nutrients within the plant. This means that irrigation should moisten entire root zone, not just a portion.

Could my problem be that the use of two localise watering points means I am not getting water to the whole root zone? The worst case scenario would be that I'm over-watering some parts and under-watering others!

What would the optimal irrigation method for a blueberry hedge be?

Answer 1

This advice from Gardening Australia may be relevant

Good quality water that is low in dissolved salts is a rare commodity in many parts of Australia, and is necessary for growing blueberries; as well a slightly acidic free-draining loam is ideal, and an open sunny aspect.

If you could tell us what kind of blueberry that would be helpful as the low bush, high bush and cultivars have different requirements.

I note that where I live the underlying soil is limestone and the water is alkaline yet native low bush blueberries grow quite well. These plants are more adaptable than they are given credit for if other conditions are right. A soil with lots of organic matter and readily available water seem to be key.

I don't know if you are able to rework your bed but in order to ensure a free draining soil I would have put a trench in the clay and fill it with four or six inch perforated drain pipe. This a modified french drain system which would ensure that the soil medium above drains well.

My recommendations are:

• test your water for dissolved salts level and pH
• ensure the planting medium is free draining by improving the drainage underneath
• while the plants are establishing water more often, by hand if needed