Site Selection: How to Grow Blueberries

Uploaded by TheUniversityofMaine on 18.10.2011

[intro music]
David Handley: I'm David Handley, the University of Maine Cooperative Extension small fruit
and vegetable specialist, and today we're going to talk about selecting a site for planting
your blueberries.
Now, when we look for a site for blueberries one of the first things you want to do is
select a site that's open and not shaded. Although blueberries will tolerate shade,
if you're after these plants for production, in other words lots of berries, then they
should get full sunlight. If you're primarily interested in having them in the landscape
and feeding the birds then sure, go ahead and put them in a partially shaded area, but
just understand you're going to lose a little bit of fruit when you go down that lane.
Now, the other thing you want is a little bit of protection. Blueberries are not adequately
hardy for all parts of Maine. So if you can have a hedge or something running along the
west and north sides to prevent those cold winds from coming and hurting those delicate
buds in the wintertime, that will help quite a bit.
One of the things you don't want to use for a hedge though is balsam fir. Balsam fir exchanges
some disease problems, specifically witches' broom, with blueberries so that's not a particularly
good plant to have around your blueberries. But some other kind of evergreen hedge will
help them get through the winter much better.
The other thing you want to be near is a source of water. These plants need water not only
for establishment but through the fruiting season, especially for facing a very dry summer,
you want to be able to get water to those plants. Get some place where you can either
run a hose to them, some trickle irrigation or a soaker hose to keep those roots well
rooted during the summertime.
Now in terms of soil types, blueberries like a well-drained soil and this is a mistake
gardeners often make. They think, "Blueberries grow in the swamp so I'm going to plant them
in a wet, soggy part of my lawn." That's not really the case. Blueberries will tolerate
wet during the late fall, winter and spring, in other words, when they're dormant. But
during the growing season if their roots are in water, the plants will drown and you'll
lose them. So pick a well-drained soil. In other words, don't look for a spot where the
water stands in the spring. Stay away from there, go a little further uphill where the
water drains away quite nicely.
Blueberries don't like heavy soil so we want to stay away from areas that are loaded with
clay. They prefer a sandy or sandy loam type soil, something that drains well and is nice
and friable like we see here. Lots of big chunks in this soil will drain very well,
the roots will be able to grow through there very well. This is the type of soil that we're
looking for. If your soil has a lot of clay or is compacted, you need to work a lot of
organic matter into that soil to loosen it up, to improve the drainages and help those
roots grow better.
Some of the things we can add to the soil to help improve that, peat moss is very typically
used for blueberries because they like a lot of organic matter and they tend to grow in
peat type soils in the wild anyway. Peat moss is a little bit expensive but if you're just
growing a few plants, this will work quite well. Remember to wet it before you incorporate
it into the soil. If you incorporate it in dry, it actually acts like a sponge and will
suck that moisture right out of the soil.
The other thing we can use is compost. Compost is just a nice source or organic matter and
will also help loosen up the soil. It can be less expensive than peat moss, especially
if you make it yourself. Just make sure it's got good drainage and also be aware that the
pH of your compost can be quite high sometimes and blueberries like an acid soil. We'll talk
more about that in a minute.
You can also use other sources of organic matter, things like sawdust for example, but
bear in mind if you use something like sawdust or just leaves or pine needles worked into
the soil, they can rob the soil of nitrogen because as the bacteria in the soil tries
to break that down it will pull the nitrogen out of the soil, make it less available to
your blueberry plants and you may find you're having a real tough time keeping those blueberries
adequately fertilized.
So I prefer something that's already broken down like compost, well-rotted sawdust or
just some peat moss pre-moistened before you work it into the soil.
Now, in terms of preparing your soil and getting ready for that, this should be done in the
fall before planting. Of course, have a soil test taken. Stop at your cooperative extension
county office, pick up a soil test box, get the little form, make a soil test the way
they tell you. We have a video on that at this website that you can look at. But be
sure on the form that you fill out blueberries because blueberries have some very specific
nutritional needs and you don't just want to put a general garden code on here. Make
sure you code for blueberries.
They'll come back and tell you what you need to do but one of the things you need to be
aware of is that blueberries are acid loving plants. They're in the same family as rhododendrons,
azaleas, mountain laurels, that group. They like their soil to be acid or sour. Usually
what we're looking for is a pH of about 4.8 to 5.2. Typically if you're going into soil
that's had lime like a lawn or a garden, your pH is going to be up around between six and
seven so you may need to acidify that soil.
What they'll recommend is that you put some sulfur on it and you can buy sulfur in little
pelletized form like this or you can buy it in a powdered form. Your soil test will tell
you exactly how much you need to add per square foot to bring that pH down to the desired
level of 4.8 to 5.2. This should be worked into the soil preferably the fall before planting
so it has time to break down and adjust that pH for you.
Now, when we're going to plant these things we want to work some organic matter into the
soil. You can do this the fall before if you want. You can add some compost to the soil
or you can work a cover crop in such as winter rye, or oats, or buckwheat, one of those things,
but when we actually plant the plants we'll be working some compost and some other organic
matter right into the soil.
Typically what I recommend is when you dig a hole for blueberries, you take the soil
that you've taken out of that hole and mix it one to one with your organic matter such
as compost or peat moss. Just work it right in there and this is what we're going to backfill
around the plant once we plant this in the springtime. So we'd put the plant in, backfill
with this one to one mixture of organic matter and soil, and our pH is at the proper level
because we put sulfur in the fall before, and we'll be all set.
So the primary things to remember are full sunlight, protection against the wind, a good
source or water, good drainage in your soil, and correct your pH to 4.8 to 5.2 and you'll
be all set.
The last thing we want to talk about is weed control. One of the things we don't want to
do is dig right into a lawn, just dig a hole in a lawn and stick your bush in there because
the grass will quickly come back in and compete with the roots of these blueberries. These
blueberry roots are only about six to eight inches deep so you need to kill out any grass
or weed species that are on that soil prior to planting.
You can do this with a lawn herbicide if you want the fall before to kill it out and plant
into it the next year. You can do it by working that grass up the year before and making sure
that it's not going to come back by working it repeatedly. Or you can just do something
like laying some old landscape fabric down or some old plastic that you might have lying
around, tar paper, whatever, put that down on the ground for several months and this
will kill out all the grass underneath.
When you pull this up in the springtime you'll have a nice bare patch there that won't have
many weeds in it. Plant directly in it without working the soil up because that'll disturb
more weed seeds to come up. You'll find that you'll put that plant in, mulch around it
and you'll have very few weed problems afterwards.
So, that's how to get your site ready for blueberries. In a little while, we'll talk
about actually planting these things.