Strawberries are very easy to grow and always produce satisfying results. It is important to understand that the strawberry plants can only develop strawberries after their white flowers have been pollinated by insects. Strawberries are the fruit of the flower.
A fruit is actually the seed bearing structure produced after flowering. The juicy, fleshy part of the strawberry carries the fruits, tiny pips, on the outside of the berry. The seeds are inside the tiny pips.
What to Plant
• Seed – Alpine strawberries are suitable for growing from seed. Gardeners do not usually grow strawberries from seed, because they take so long to grow into a decent size plant.
• Strawberry runners – It is much easier to plant strawberry runners in the autumn, which will crop in the following summer. Runners are small plants with long roots & a few tiny leaves which have grown out of the mother plant on a stem.
• Pot-grown plants can be planted in the spring.
• 60 day strawberries are more expensive. These will fruit 60 days after planting – and yield well in the first year.
Which Variety – Grow one row each of early, mid-season and late- cropping varieties to spread the season.
How Often to Plant – Each strawberry plant will fruit for four seasons and then they will need replacing.
Use a Reputable Supplier to ensure the plants are disease free.
Where to Grow
Strawberries need a sunny position with fertile, well-drained soil.
Strawberries can be grown:
- Directly in garden soil, as long as it is deep & well drained
- In raised beds
- Window boxes
- Table tops
- Containers or gro bags
- Vertical walls
When to plant strawberries – July to mid September. Or pot grown plants anytime.
How to plant strawberry runners
• Dig the soil & add well-rotted compost or farmyard manure and a handful of general-purpose fertiliser per square metre.
• Plant in rows, called beds, spacing plants 35cm apart. Rows should be at least 75cm apart.
• Dig a hole large enough for the roots, and spread the roots out in the hole. Plant them quite shallow, with the base of the crown (the central growing point) at soil level, so that they do not rot. Firm them down and water well.
Looking after strawberries
• Weed the bed in spring & regularly through the summer. Take care not to disturb the strawberry plants as they have shallow roots
• Apply 100 gram per meter of sulphate of potash or a general fertiliser in the spring
• After flowering, watch for slugs
• Place straw, or strawberry mats, under leaves to keep fruits dry & prevent mould.
• Water the strawberries in a dry time, but try not to soak the leaves as it will encourage moulds
• Cover the beds with netting to keep the birds off. Wire netting will protect the strawberries from squirrels.
• Remember insects must be able to access the flowers for pollination.
• Harvest the strawberries, when they are red all over, every day.
• Cut runners off & discard as they appear.
• When the plants have stopped producing fruit, cut all the old leaves off and remove the straw. Take care not to damage the crowns (the central growing point) which should be left in tact.
Putting Straw under strawberries
Reasons of using straw under the strawberries are:
• the fruits grow out onto the straw, and are kept off the soil, so the strawberries are clean
• the straw stops weeds growing
• the straw acts as a mulch and conserves moisture
• the straw protects the strawberry plants against late frosts
• the straw holds the fruits up, allowing air to circulate freely, which keeps the fruit healthy & less prone to fungal diseases like mould
• the straw breaks down into organic matter which will eventually enter the soil & feed the plants
Possible alternatives to straw:
• plastic membrane – plant strawberries through a plastic membrane. The membrane will keep the soil moist & stop the fruits coming in contact with the soil. But I found the strawberries tended to ’sweat’ on the plastic membrane, and then rotted.
• wood chips – slugs were a problem
• Strawberry mats are a nice, clean alternative.
1. Frost – late frosts can kill flowers. Listen for frost warnings on the weather forecast & cover the bed with horticultural fleece if there is a danger of frost.
2. Kinks – Strawberries grown in pots are sometimes sour. This is due to the kink in the stem which forms when the stem falls over the sharp edge of the pot. To avoid this introduce round edges by placing a round pipe under the kink, or support the fruits so that they do not weigh the stem down
3. Slugs – Slugs like strawberries and spoil the berries.
To reduce slug attacks on strawberries:
• surround the strawberry row with oyster grit, or a similar medium like gravel, which the slugs do not like to move across.
• place ’slug pubs’ amongst the rows. These are small containers of beer which the slugs drop in to.
• leave grapefruit or orange skins in the row, which will attract slugs, & pick the slugs out every day & destroy.
• elevate the strawberry plants on poles which the slugs cannot climb – see table top strawberries
Click this link for more information on slug control.
Slugs can devastate the strawberry crop, so it is worth taking time to control the slugs, using a number of different methods.
4. Grey Mould
Wet weather causes strawberries to suffer from grey mould, particularly if it is rainy & drizzly over several days.
Grey mould is caused by a fungus Botrytis cinerea which spreads in wet conditions around 15 C.
Symptoms of Grey Mould
The rot usually starts at a point of contact such as the soil or other fruits. The berry turns brown and remains firm. White mould is sometimes seen, and the whole berry can rot.
Control of Grey Mould –
• is by inspection and hygiene. Always take a paper bag when inspecting the strawberry plants & place infected fruit in the bag to avoid spreading the spores.
• Carry out inspections when the plants are dry & dew has dried, to avoid spreading the spores in ideal conditions.
• Avoid misting the plants, or overhead watering, if Botrytis is a problem.
• Give plants plenty of space, to allow air circulation and rapid drying of leaves.
• In autumn, cut stalks at or below ground level & remove all strawberry plant debris from the garden, but leave the crown. This is to prevent overwintering of the fungus as tiny, black sclerotinia in dead leaves and stalks.
• Fungicides are available to control Botrytis. Always follow the manufacturer’s instructions on the packet.
Many strawberries have just a small patch of grey mould. This can be cut off, and the remaining strawberry can be used to make a strawberry sponge!
How to Pick Strawberries
Picking strawberries is an art, if the strawberries are to remain bright and unbruised.
Teaching enthusiastic children how to pick strawberries is well worthwhile.
The aim is to :
• break the strawberry stalk without actually touching the berry
• end up with a stalk about 1 cm long attached to the strawberry
• not squeeze the strawberry at all
The method of picking strawberries:
• surround the strawberry with your hand, and with the fore-finger & thumb nail pinch the stalk about 1cm from where it is attached to the strawberry
• twist the stalk so that it breaks off
• let the strawberry roll into the cup of your hand so it rests gently in the palm
• carefully place the strawberry in a bowl
• do not overfill the container or the berries at the bottom will get squashed
- Strawberries are very tender & bruise easily.
- Once bruised they will start to deteriorate and rot.
- Bruised strawberries loose their bright appearance and the colour darkens.
- The strawberry must not be held in the fingers and pulled off the strawberry bush, because the pressure of the fingers on the berry will bruise it.
- It is important to pick strawberries with the hull intact.
- Do not wash the strawberry until you are ready to use it. Wet fruit will go off. So don’t pick in the rain unless you plan to eat the fruit immediately!
Growing New plants from strawberry runners
Most varieties of strawberries produce runners (long stems) which produce plantlets along their length.
These runners will sap the energy from the mother plant, and are usually cut off as soon as they are seen. But some growers allow them to grow and root between the plants, so that a continuous mat of strawberry plants is formed. Alternatively, the runners may be used to propagate new strawberry plants.
It is easy to raise new strawberry plants from runners:
• Strawberry runners must originate from a healthy mother plant.
• Select a healthy plantlet on a runner, in June or July
• Cut off the runner beyond the plantlet
• Fill a pot with compost. This pot can be buried in the ground, close to the plantlet. If the strawberries are grown under plastic, the pot will have to be kept above ground.
• Peg the plantlet to the compost, but leave it attached to the mother plant.
After a few weeks, the new strawberry plants will be big enough to be planted out. The runner, connecting the new plant in the pot with the mother plant, can be cut & the peg can be removed.
New roots have grown down and out of the bottom of the pot, as shown in the picture of the bottom of the pot above.
The new, young strawberry plant is now independent and able to feed itself. The plant must be watered regularly whilst it is in the pot, to keep it damp.
Grow the young plants on, allowing them to become well rooted, and plant them out in the autumn.
* Plant them quite shallow, with the base of the crown at soil level, so that they do not rot.
* Start a new bed with the new runners.
* Strawberries should only be grown in the same place for 4 years and then moved on. This is because viruses and pests build up in the soil which reduce the crop.
New strawberry plants from runners will keep the strawberry patch vigorous.
End of Season Care
Immediately summer strawberries have finished cropping, the old tops are removed. This involves cutting off all the leaves, new and old, and
removing all plant debris. Care must be taken not to injure the crowns (the central growing point, just above soil level).
This process of removing the leaves prevents the overwintering of botrytis & other pests and diseases.
Cover the strawberries with netting in winter, to keep the deer or rabbits off. It is important to stop pests from damaging the crowns.
Other ways to grow strawberries
Table Top Strawberries
Table top strawberries have less pests – slugs cannot climb up to the table tops, & fungi do not like to be in such an exposed position!
Not having to bend to pick the strawberries is an added bonus. Click this link to read about a Pick Your Own Grower who was surprised to discover how popular his table-top strawberries were!
One problem with table top strawberries is that they are at the right height for the deer to eat the leaves. Also they are very prone to frost damage. Stuck up on the tables, cold air can circulate round the strawberry bags and there is little protection.
Strawberry walls are now superseding table top strawberries as a growing technique.
The big advantages of a vertical strawberry wall are:
• save space
• produce more strawberries per metre than table tops
• uses 4 times less water than table tops growing strawberries in peat bags
Ramsey Horticultural Society have shown that anyone can grow fruit & vegetables, even if they are short of space, by using a bra as a container & growing the plants in a bit of compost in the cups.
Once the bra is filled with compost you can grow alpine strawberries in them. Georgie Webb of the Royal Horticultural Society said:
‘The bigger the bra the more you can grow. But the serious message behind the “bra-skets” is that you do not need a lot of space or even a lot of money to start growing your own food – just a bit of imagination.’