How to Grow Alpine Strawberries
Alpine strawberries are relatively easy to
grow but they can be frustrating even for experienced gardeners.
In many ways the germination process is the most tricky
and can be the most frustrating. We start of with some germination
tips and move on to some thoughts on a couple of other subjects
regarding growing alpine strawberries..
Germination Tips
I’ve found it best to germinate seeds with
capillary matting (or wicking systems) kept moist at all
times. Surface sow them and don’t cover them. I like to
put a tiny bit of white sand on them just to make sure they
are held down on the surface. The sand also aids in seeing
whether the cells are drying out. Don’t let the soil dry
out even for a few hours. Putting on a dome or seran wrap
with a rubber band will also help but make sure to take
off to let in some fresh air from time-to-time. It's usually
sufficient to do this when you are checking the seeds to
see if they're germinating.
Once the seeds have germinated, take off the
cover to avoid conditions that lead to disease. Light aids
in germination so keep in a bright window, greenhouse, or
under lights, but beware that such conditions can dry the
surface of the soil which is where the seeds are germinating.
And, dry soil even for a few hours is not a good thing when
germinating strawberry seeds.
During germination indoors I use florescent
bulbs, one daylight and one cool white, on for 14 hours/day.
I also freeze the seed for 3-4 weeks before seeding to make
sure that dormancy has been broken. It's been reported that
red light helps with germination as do some chemical applications.
I use neither method and have not felt a need to do so -
nor do I want to introduce chemicals into the process.
The seeds can also be germinated outdoors.
Make sure you have an area protected from the wind such
as a cold frame. The seeds are tiny and the wind can blow
them away. A little straw or dried grass clippings can be
used to hold them down and to act as “mulch” to keep the
soil most. Just don’t cover too heavily since they need
light to germinate.
Temperature is important. They will germinate
above 75 degrees F, contrary to some published reports but
it's best below that temperature. I find it best indoors
to be between 65 and 75 if possible. My unheated garage
works great for this. Extremely low temperatures won’t hurt
but will delay germination.
Strawberry seeds require a lot of patience.
Don’t give up on them. I’m germinating a plug flat right
now. The first seeds germinated in 7 days. At 21 days seeds
are still coming up. It can take as long as 6 weeks or more
for all of the seeds to come up. The minimum germination
standard is 60%. Most varieties will germinate at 80+% and
higher. I prechill the seeds in a refrigerator prior to
shipping. It’s best to store them in a refrigerator if there
will be a delay in sowing. They should be frozen for 3-4
weeks as mentioned above before seeding. This also aids
in germinating old seed.
A note about seed age. Strawberry seeds
stored in refrigerated conditions and kept dry should germinate
well for about 2 years. Most states require an expiration
date of one year on packaged seeds. I've had refrigerated
seeds germinate after as much as 6 years though the percentage
germination was low (15% or so). It's always best to get
fresh seed if in doubt. You don't want to miss a season
without these berries, do you?
After germination the moist conditions can
lead to seedling diseases like damping off. I use a small
oscillating fan to keep air moving and have not had a problem
with such diseases. These varieties grow and produce best
in full sun but will tolerate some shade. Alpine strawberry
seeds should go from seed-to-seed as they say in 3.5 to
4 months. This means that 3.5 to 4 months from the time
you seed them your first fruit should be ready to pick and
eat.
Up Potting
Depending on the size of container you are
using for germination, you may need to up-pot the seedlings
one or more times before transplanting into their final
container or the garden. If you have questions about this,
please contact us,
Usually at around 2 months after seeding,
the plants are ready to transplant. I move from plug trays
or cells to 1801 inserts. This means that there are 18 cells
that separate individually in a 1020 flat. I like to use
the deep 1801's so there is more soil in the cell and less
chance of drying out. Each cell in this size system is 3.5"
x 3.5" x 2.5" deep. 4" inch pots work well
as well. You can also transplant directly into hanging baskets
at this point.
Once the plants have filled the container
used and described above, I typically transfer them to their
final container or to the raised bed that I use. At this
point they are cared for like any other strawberry. They
need an acid fertilizer such as 20-20-20 if you are in a
conventional system and not growing organically. In the
past I used half strength fertilizer at every watering.
Soil should be kept moist, not soggy. The soil can dry out
between waterings to some degree. I've had mature plants
"go down" completely and still recover after being
watered but I wouldn't advise letting it get to this point.
It only points out that they are tough plants.
Propagation by Division
Mature plants should probably be divided at
least every three years. They will produce for years with
proper care. Here I'll go into my little speach about spacing
and container size. It's widely reported in print literature
and on the internet that plants should be spaced anywhere
from 6 to 12" apart when planted in beds. For some
reason it's widely reported and diseminated that the plants
are real cute along walkways and as border plants. I just
shivver when I read this. Why would someone exile a plant
that has fruit that tastes divine to a border. I'm a firm
believer in giving them as much space as they need to get
maximum production of the "out-of-this-world"
fruit. If I could afford it, every plant would go into a
half barrel.
Alpines vs Garden Varieties
Keep in mind that alpine strawberries are
different than your run of the mill garden variety strawberries.
They are not only more fragrant and more tasty, they grow
differently. Garden variety strawberry plants increase in
size but not in the same way as an alpine. Alpine strawberries
produce many growing points as they mature. For this reason,
division of the plants is one effective way to increase
the number of plants you have. I've divided two year old
plants and got nearly a hundred viable divisions. I don't
recommend division to this extent unless you have rare specimens.
"Over dividing" will set back production possibly
a whole season and no one who enjoys these little berries
wants that. It's usually sufficient to divide the plants
in half or quarters and still maintain production. For guidelines
on propagation by division, consult a textbook or contact
me. I'd be glad to explain the process. Perhaps, as this
website grows details of division can be added if enough
people are interested.
Pollination
Pollination is an important aspect of growing
strawberries. It's not usually an issue when the plants
are grown outdoors in-season. By in-season we mean during
the normal growing season when there are insects such as
bees present. A lot is being said recently about declining
bee populations so it's appropriate to comment on methods
to increase the likelihood of pollination.
Out-Doors
The literature mentions that the herb borage
is a good companion plant for strawberries and may even
have the effect to improve the taste. For the spring of
2008 we have planted some borage to observe the behavior
of bees and to see if there is anything to the taste improvement
suggestion.
We have observed in the past that bumble bees
are especially attracted to clover in our lawn when the
clover is allowed to bloom. The small white clover actually
doesn't lose all of its flowers after mowing on a high setting
with our mower. This small white clover tends to attract
honey bees and other insects to its blooms.
Another type of clover with the large pink
blooms doesn't make it after mowing but we have a couple
of areas where this clover has been blooming regularly in
the summer. Bumble bees seem to like it and an internet
search showed that this is common knowledge. We picked some
seed from a pink clover plant that had gone to seed in a
vacant lot near us and planted it. It overwintered this
past winter in a pot. I have to admit that it's hard to
keep it watered enough because it is a monster plant even
in a 6" pot. Some tests are planned with clovers in
2008 as well.
Indoors
Pollination indoors can be an obstacle to production. In
greenhouse setting the problem has been overcome with the
use of commercial bumble bees that can be purchased nearly
year-round from several sources. In one's home it's a different
story. Hand pollination can be done with the small brush
or one can use an appliance that vibrates such as an electric
toothbrush. When I had greenhouses I used a vibrating seeder
(which I still use for seeding and counting seeds). It's
a good idea to do it daily if you can but literature says
every other day is sufficient. And, it's best to do it after
the dew has "burned off". Touch the vibrator to
the bloom stalk for a couple of seconds.
Another good practice is to use an occillating
fan indoors. It serves two purposed. It gets the air moving
so a level of pollination can occur due to the "wind".
It also helps to keep the plant and fruit drier which reduced
disease incidence.
FAQ's - we have compiled answers to
subjects brought up frequently. Click
FAQ's to take a look at these.
More to Come .....
I'll stop here for now. When I have a little
more time I'll get into field production and deeper into
container growing details. As always, if you have any questions,
don't hesitate to ask.
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