Strawberries have become very popular in the United States because of their year-round availability, affordability, and health benefits. Whether you love eating them with cream on a cool summer evening or enjoy them in your morning smoothie bowl, strawberries are a treat.
According to the Colorado Integrated Food Safety Center of Excellence, an average American consumes around 8 pounds of strawberries each year (source). 75% of those are fresh strawberries that come straight from the garden to your table.
In this blog, I will share some guidelines on how to grow farm-fresh and juicy strawberries in a greenhouse. I have been doing so successfully for the past 5 years, and now I would like to share my knowledge with you all. Happy reading!
Growing Strawberries in a Greenhouse
Can you grow strawberries indoors in a greenhouse? Yes, you can! Additionally, you can also enjoy fresh-picked greenhouse strawberries all year round.
If you are looking to diversify your greenhouse, strawberry plants are the first edible crops you should consider growing since they are easily adaptable to greenhouse production systems.
In this section, I will share some exciting facts about the types of strawberries. I will also share a step-by-step guide on growing strawberries in a greenhouse, so you have all the information you need before you dive in!
Scientific Facts about Strawberries
- Strawberries contain eight comprehensive sets of chromosomes in each cell. This is why their growth is an accomplishment for every gardener (source).
- Strawberries grow in every province in Canada and every state in the United States. (source)
- A strawberry is the only fruit that has seeds on the outside rather than the inside. One strawberry has about around 200 seeds on average. (source)
- Strawberries are low in calories. According to the US Department of Agriculture’s National Nutrient Database, one large strawberry has only six calories. (source)
- Strawberries have high levels of nitrate. This increases blood and oxygen flow to the muscles. (source)
Types of Strawberries
There are 3 different types of strawberry plants. As a gardener, you must know the differences between each of these types before growing strawberries indoors to achieve your gardening goals. The 3 types are:
June-bearing strawberries are the highest-yielding, most popular, and affordable strawberries available in the market. They take 2 to 3 weeks to grow and are grown in 5 seasons:
- Early season strawberries fruit in the late spring season.
- Early mid-season strawberries start bearing fruit 4 to 5 days after the early season variety.
- Mid-season strawberries start producing fruits approximately eight days after early season types.
- Late mid-season strawberries begin to bear fruit about ten days after early season strawberries.
- Late season strawberries will produce their berries approximately 14 days after the early season ones.
Everbearing strawberries have 2 harvests each year.
These are cultivated using the hill growing system. In this system, all the runners (stems that run above the ground and produce new clone plants) are separated, so only the initial parent plant remains. Separating the runners causes the mother plant to produce added flower stalks and crowns.
Day-neutral strawberries are one-of-a-kind. These strawberry plants yield berries from April to October in an open garden space. Nevertheless, in a greenhouse, you can grow them all year round.
Day-neutral strawberries yield a wholesome harvest in the first year and bear fruit if the temperature stays between 32 to 82 degrees Fahrenheit.
Just like everbearing strawberries, these are planted using the hill-system. However, day-neutral strawberries are much smaller than everbearing and June-bearing strawberries.
How to Grow Greenhouse Strawberries: A Complete Guide
Step 1: Create Ideal Conditions
Strawberry plants have shallow roots. They require plenty of sunlight to thrive. Your goal must be to provide the maximum amount of sunlight as possible by keeping the panes and doors of your greenhouse clean at all times, so there is nothing in the way to obstruct out the light.
Ideally, strawberry plants need 6 hours of sunlight each day, although some varieties might need up to 12 hours. Hence, you must choose your greenhouse site carefully and ensure that the site allows adequate sunlight to reach the plans.
With little light and photosynthetic movement, strawberry plants will not be able to bear many healthy fruits.
Strawberry plants require well-drained and acidic soils, which are rich in nutrients. They need high concentrations of organic matter. You must fertilize your strawberries 2 times a month with a well-balanced, nonchemical compost during the developing period.
The optimal soil pH should lie between 5.4 and 6.9. To keep the roots cool and humidity low, you must combine a mulch layer or straw throughout the top surface. Right after the strawberries start to bloom, use high-potash liquid fertilizer to maximize the plant’s ability to bear fruit.
Strawberry plants thrive well when the ground is wet. In warm months, they need frequent watering. However, they do not like to sit in the water-logged ground since this can weaken the green crown and cause the berries to rot.
You must water strawberries at their base (video).The ideal time to water these plants is early in the morning so that the water will not dry out fast. Provide about an inch and a half of water each week for best results.
Strawberries prefer cool to warm weather to bear fruit. You must ensure that the temperature in your greenhouse does not rise over 75 degrees Fahrenheit because high temperatures kill pollens and hinder the plant’s development.
It would help if you kept the greenhouse temperature between 65 and 75 degrees Fahrenheit till the strawberry plant starts flowering. Decrease the temperature once you have harvested the strawberries so that it stays cold throughout winter.
A cool phase is essential to stimulate them to flower the next season. This only matters if you choose June-bearing or everbearing strawberry plants.
Garden pests, such as spider mites, beetles, slugs, and snails are a massive problem for strawberries. Diseases such as gray mold and powdery mildew can cause severe losses to your harvest.
You must maintain greenhouse cleanliness and continuously be on the lookout for diseases to prevent them from spreading. You must also remove any dead foliage because it can harbor pests and diseases during winter.
Step 2: Plant Strawberries
The first step is to purchase disease-free strawberry seedlings from a well-known local nursery. Next, you must plant the seedlings in the ground, planters, pots, raised beds, or hanging baskets for strawberries.
Please make sure the hole you dig is deep enough to house the roots without bending them. Make sure the strawberry crown remains just above the surface. Do not sow them too deep as this can cause rotting.
If you’re growing strawberries in hanging baskets, avoid hanging the baskets in an area that receives many breezy winds. Three to four strawberry plants are enough for a 12-inch wide strawberries hanging basket.
Strawberries grow best in pots kept in direct sunlight and that have a high-quality potting mix-compost soil. Do not crowd them in the container. Leave at least 8-inches between each plant. The pots should be at least 6 to 8 inches in diameter and have many holes for drainage.
Step 3: Harvest Strawberries
Strawberries are ready for harvest, usually 5 weeks after the flowers blossom. Harvest them quickly as they ripen, or they will rot on the plant. Monitor them every other day throughout the ripening season.
Pick them every 2 days when it’s time to harvest. Do not pull the strawberries; just cut or pinch them down, leaving a half-inch of the stalk. When the last strawberries have been harvested, remember to remove the mulch.
Frequently-Asked Questions about Growing Strawberries in a Greenhouse
Q1. How Do You Grow Strawberries in a Small Greenhouse?
If you have a small greenhouse, you can grow small varieties, such as day-neutral strawberries. If you do not have enough floor space, you can use hanging baskets and plant the seedlings in them.
Q2. Can You Grow Strawberries in a Cold Frame?
Yes. Strawberries are versatile plants that can grow in a cold frame under glass. They do like a bit of frost and good soil. They have shallow roots, so spreading is not a huge problem. A cold frame is ideal for keeping birds off and also makes it easier to control slug attacks.
Q3. What is the Best Time to Plant Strawberries?
The best time to plant strawberries is after the frost threat has passed, i.e., in late spring or early summer. It would be ideal if you plant them between March and May.
Final Thoughts on Growing Strawberries in a Greenhouse
To sum it up, growing greenhouse strawberries is not easy. You need to monitor the environmental conditions carefully and watch out for pests. If you are a beginner, read this article thoroughly before you begin the process. Remember to:
- Buy disease-free seedlings.
- Ensure plants have enough space to grow.
- Provide plenty of sunlight and water at the base.
- Use well-draining soil with compost blend.
In the comment section below, let me know if this article helped you grow a batch of utterly delicious and healthy strawberries. I can’t wait to hear about your experience!