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..
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.
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 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.
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.
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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