Welcome to Top of the Crops! Today, you will learn about growing strawberries (in a polytunnel). Follow this in-depth guide on how to grow strawberries in the UK.
Strawberries are one of the most popular polytunnel crops and it is easy to see why. These delicious fruits are very easy to grow and to care for successfully. And as perennial plants, they will not just enhance your garden for a single season but will fruit over a number of years.
Garden strawberries, Fragraria x ananassa, are the most common choice for polytunnel growing, though you might also consider wild or alpine strawberries – Fragraria vesca - as an alternative for a shadier spot. In this guide, we will focus on the former.
There are two main categories of garden strawberries – summer fruiting strawberries, which fruit in early to mid summer, and perpetual types, sometimes called everbearers, that fruit over a long period from early summer to the first frosts.
Summer fruiting strawberries are by far the most common, and are typically divided into early, mid season and late fruiting varieties.
Strawberries are versatile plants when it comes to how we can integrate them into our garden designs. Of course, we can grow them in the ground, in dedicated strawberry beds or patches, in mixed perennial planting schemes, as bed edging etc...
But we can also grow them in a wide range of different containers, from hanging baskets and vertical garden strawberry planting pockets, to traditional strawberry pots or other simple container options. And thinking about innovative space-saving solutions can help us grow more in our polytunnel gardens.
Growing strawberries in a polytunnel can be beneficial because it can protect the plants to a degree from birds and other creatures that will try to eat your crop. It can also provide warmer conditions that means you can have a slightly earlier harvest from polytunnel strawberries than from those grown outside.
For growing strawberries in the ground, in a polytunnel, a greenhouse, or fruit cages, follow this table.
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Strawberries are planted in the spring or in late summer or early autumn. They should be planted out no later than the first week of September in northern regions, and the second week of the month in southern areas. Typically, cropping from a late summer/ autumn strawberry planting (UK) will be better as the plants will be better established by the time the harvesting period rolls around.
Strawberries need a location that provides them with:
Full sun, or very light/dappled shade.
A sheltered spot, not an exposed location or a frost pocket.
Moist yet free-draining, fertile soil or growing medium.
Remember these basics and you will not go too far wrong.
To grow strawberries you will need:
Strawberry plants.
Pots or other containers, or a suitable bed or border if you are growing in the ground.
Suitable soil or potting mix.
The means to water or irrigate your strawberry plants.
Organic mulch materials. Straw is traditional.
High potassium organic liquid plant feed (such as comfrey tea) when growing in containers.
Strawberries are not difficult to grow at all. You simply need to decide where you will grow your strawberries and then you can follow the simple instructions below.
Select which strawberry variety or varieties to grow.
Prepare the strawberry planting area.
Dig a hole to accommodate each strawberry plant, placing each one around 35-40cm apart, in rows 75-100cm apart.
Place the strawberry plants in the holes and firm the soil gently back around them. Make sure you plant them at the right depth, with the crown's base resting lightly on the surface not planted too deeply or it may rot.
Water the plants in well and mulch around them with organic matter or biodegradable mulch matting.
Choose and purchase your strawberries.
Choose a container and fill it with a suitable peat-free growing medium. Remember that there are many different container options to consider.
Plant strawberries, keeping these at the right depth, as when planting in the ground. The spacing in containers is generally around 10-20cm between plants.
Pots can be placed indoors or under cover in a greenhouse or polytunnel for an earlier harvest and to protect them from frosts.
Remember that plants in pots or other containers typically need to be watered more frequently and need more water than those growing in the ground.
Summer-bearing strawberries produce a harvest in early to mid summer, usually in June and July. These are usually ready when they are a vibrant red all over.
It is best to pick strawberries, if possible, during the brightest and warmest part of the day, as they will be at their most flavoursome and sweetest during this time.
Strawberries are usually propagated from runners, the plantlets that form on long stems that reach out from a parent plant. Runners can be directed and potted up or planted and will root to produce new plants.
Once well rooted in pots or in the ground, they can be severed from the parent plant and if necessary, moved elsewhere.
Propagating strawberry plants from runners can help ensure the longevity of your garden, because these new plants can be used to replace original strawberry plants, which should usually be replaced after 3-4 years when they tend to drop off in fruit production and quality.
Water well and consistently throughout the growing season, aiming for the soil and trying to avoid getting water on the crowns of the plants or on the fruits. Remember that you will need to water more when growing strawberries in containers than when growing them in the ground.
Mulch around the base of strawberry plants to protect the soil, reduce moisture losses and weed growth, and to provide protection for fruits as these form. Straw is typically used, though mulch matting is also now fairly popular.
Protect plants with cloches or fleece if a late frost threatens when the plants are flowering or setting fruit.
Using a polytunnel or fruit cage can help to protect strawberries from birds and certain other pests, though of course certain pest problems can still arise, even inside a polytunnel or fruit cage. Vine weevils, slugs and aphids, for example, are pests you might encounter.
Other common problems when growing strawberries include strawberry black eye, verticillium wilt, and a number of strawberry viruses.
Making sure that there is rich biodiversity in your garden, and ensuring optimal growing conditions for your plants can help to keep them healthy and happy over time.
Some good companion plants for strawberries include:
Asparagus
Onions and other alliums.
Borage.
Thyme.
Sage.
Oregano.
Dill
Catnip
Yarrow
Marigolds
When choosing strawberries, you will discover that there are a great many different named cultivars to choose from. Some that are highly recommended include:
Alice
Cambridge Favourite
Finesse
Florence
Hapil
Honeoye
Malling Centenary
Pegasus
Rhapsody
Symphony
Vibrant
Of course, these are just some of the many summer fruiting strawberries that you might consider. Remember that there are also everbearing and alpine strawberries that you might choose for certain areas of a garden.
When buying strawberries, it is a good idea to look at varieties that have received an award of garden merit from the RHS, those listed above, since these should do well here in the UK. You should of course look at yields and flavour, but should also consider the time of harvest, and other distinguishing factors.
You can purchase young plans from the late spring into summer, in pots or packs of plug plants.
Or you can purchase runners with clumps of roots and few leaves in late summer or early autumn, or in the early spring.
Cold stored runners are also available from late spring to early summer that will fruit for you 60 days after they have been planted.
It is important to purchase from a reliable source so that you do not introduce diseases or end up with plants that are not true to type.
Make sure that you consider how to integrate strawberries into overall plans for the space. Think about how you can use the vertical as well as the horizontal space and make the most of every inch of space available.
Select strawberry varieties suited to the growing location as well as to your own particular needs and wishes.
Make sure you mulch, for fertility with compost upon strawberry planting and with straw or similar for protection in the summer months.
Use water wisely and water carefully to avoid introducing any problems when growing strawberry plants.
Ensure good ventilation within the polytunnel to reduce the incidence of disease.
Protect plants with physical barriers and with companion planting and wildlife friendly organic gardening techniques. Make sure pollinators have access to the polytunnel at the crucial times.
When you have grown strawberries successfully you can of course enjoy them fresh from the garden or in a range of delicious recipes.
Olive Magazine. (n.d.) 29 Strawberry Recipes. [online] Available at: https://www.olivemagazine.com/recipes/collection/best-ever-strawberry-recipes/ [accessed 13/12/23]
