How to sow strawberry seeds (indoor cultivation)

Strawberry plants are easiest to grow from runners or transplants, but you can also use these tips to grow new plants from seed. This tutorial will give you tips to be successful no matter what type of strawberry you’re growing.

Once your strawberry seeds have germinated, here are my best tips for growing strawberry seedlings.

Growing strawberries from seeds

After years of growing strawberries from store-bought plants or by propagating runners from existing plants, I decided to try growing new plants from seed.

If you just want fresh, garden-fresh strawberries this season, start with seedlings.

Growing strawberries from seed takes much longer, and you might not get any fruit this year, but it can be quite rewarding if you enjoy a bit of a challenge, are simply curious, or both.

I have tried many different growing methods.

My testing involved following recommendations from other growers as well as unusual (and often highly misleading or fabricated) tips from TikTok and Instagram.

Spoiler alert: planting whole or sliced ​​strawberries directly into soil will not produce strawberry seedlings, and even if they do grow, it will take longer than the two years I waited.

Here are my top tips for growing from seed:

1) Use fresh seeds

Strawberry seeds can be viable for five years, but the highest germination rates were seen in seeds less than two years old.

By the way, I have only had success with commercially available seeds, not with seeds harvested from fruit.

If you try this, make sure you buy fresh seeds.

2) Store in the refrigerator for 30 days before sowing.

Not all strawberry varieties need this treatment, but many do, so if you’re not sure, just leave them in a cool environment (in the fridge) for a while before sowing them. It won’t hurt, and it might even help.

3) Sow the seeds on the surface of the potting soil. They need light to germinate.

This may be the biggest reason why attempts fail: if the seed is buried, it will not sprout.

With these tips in mind, let’s go through the process.

How to sow strawberry seeds

When to sow strawberry seeds

This is best started in late winter, which allows plenty of time for the seeds to sow and grow through the spring and summer, and the plants should be established in the ground by autumn.

For future reference, keep notes on your phone or in your gardening journal with dates, observations, and actions taken. At the very least, take some photos as you work.

In this example, we would start the process in March in a climate like here in Ontario, where the main outdoor growing season is May through October.

Preparing to plant strawberry seeds

march

The first step is to chill the seeds in the refrigerator for at least 30 days.

Refrigerator temperature should be between 34-39°F (1-4°C).

Exposure to cold, winter-like conditions before sowing is called “stratification” or “vernalization”, depending on the situation.

We call this stratification, and we have a detailed guide on stratifying seeds here.

Stratification can be “wet” or “dry”.

To dry stratify, place the packet of seeds in a sealed food storage bag in a consistently cool place in the refrigerator for 30 days (or more). To wet stratify, scatter the seeds on a plate of damp paper towels, sand or potting soil and place in a sealed food storage bag in the refrigerator for 30 days (or more). Check every few days and re-moisten if necessary.

Note

The dry stratification method gave me the most consistent results, and I think this is because it was easier to sow the dry seeds on the surface of the potting soil.

The quick way

The rapid method takes a week instead of 30 days, and I’ve heard other gardeners say it works for them, but the results were not lasting for me.

For this method, place the seeds in a zip-top plastic food bag with a small amount of moist sand or potting soil. Place in the refrigerator for 24 hours, then transfer to the freezer. After another 24 hours, place back in the refrigerator for at least 7 days.

Read here for more information: Fridge-freezer method for delphinium seed germination tricks (cold stratification in the fridge).

Stratified strawberry sowing

April

After 30 days in the fridge, the seeds are ready to plant.

You can plant them in any container with drainage holes wherever you have space.

for example:

A plant pot (at least 2-3 inches tall and wide) A plant tray (at least 2 inches deep)

The larger the pot, the less you’ll need to transplant it later, but it will take up more space indoors.

Fill a flower pot or tray with moist potting soil.

Place the seeds on the surface of the potting soil.

The combination of contact with moist potting soil and exposure to light will cause the plants to germinate.

You can choose to plant the seeds now (about an inch apart) or scatter them and thin them out later.

Place it under a grow light or near a sunny windowsill.

Avoid strong sunlight and keep the soil from drying out.

I use a simple grow light on a timer for about 12 hours a day, you can see my grow light setup here.

The optimum soil/potting mix temperature for strawberry seeds to germinate is 18-24°C (65-75°F).

(Optional) If the relative humidity in your home is low (below 40%), cover everything loosely with clear plastic wrap (food wrap) to help retain moisture. Remove the wrap when water pools on the plastic or the seeds begin to sprout.

Set a reminder on your phone to check on your seeds every few days.

If necessary, water the tray from underneath or use a spray bottle to keep the potting soil moist. Watering the potting soil directly can wash away the tiny seeds.

I like to use a moisture meter to check the moisture level of my potting soil, but you can also use your fingertip.

What to Expect

May to July

Strawberry seeds can take weeks or even months to germinate, and you may not notice them at first because they’re so tiny.

In some cases the seeds sprouted as soon as 10 days after sowing, in others they sprouted after waiting as long as five months, but all from the same seed.

Plus, they all vary in size at first, some small, some big, but they all have the same number of leaves, and I leave them all because it seems like the smaller ones will eventually catch up.

Seedling care

To continue, plants need plenty of water and light.

Ideally, you want at least 12 hours of light per day – I use grow lights with a timer so I don’t have to worry about the hours of sunlight.

Led Grow Light

Recommended LED Light

Saplings | Barrina Super Bright White LED Light | Amazon

These lights are perfect for starting seeds or growing young plants indoors until it’s time to transplant them outdoors.

Flowering and fruiting indoors | Barrina Full Spectrum LED Light | Amazon

If you need lighting for long-term growing, such as indoor flowering or fruiting plants, choose full spectrum bulbs.

Potted plants

The term “repotting” simply means moving a plant to a larger pot.

Once the seedlings have a strong stem and several leaves (three or more), they can be transplanted into individual pots if desired.

These plants tend to have lots of delicate roots that grow vertically and horizontally in the soil and get tangled up, so I like to give each plant its own container.

Transplanting outdoors

June to August

Before transplanting your strawberry seedlings outdoors, you need to make sure the timing is right to plant them and allow the seedlings to “acclimate” themselves first.

“Hardening” means gradually adapting your plants to outdoor conditions over a period of time. Learn how to harden your plants here.

Some strawberries are more cold hardy than others, but you will usually need to wait until all danger of frost has passed and the soil temperature is stable at around 60°F (15°C).

You can continue to grow your strawberry plants in pots or transplant them into the ground.

Young plants are very delicate and therefore prefer to grow them in containers where they can be protected from harsh weather and, later, from animals when the fruits form.

fertilizer

Pots – If fertilizer wasn’t added to your potting soil, you can add it now by following the product instructions for your potted seedlings. In-ground – Add organic fertilizer to the soil if it needs it. I use homemade compost. If you have the space, plant the plants 1-2 feet apart. This will make it easier for them to propagate runners (new shoots that will produce the next generation of plants) later.

Flowering and fruiting

The new plant will probably not bear fruit in the first year.

Protect it with a thick (4 inch) layer of leaves or straw during the winter, then remove the cover in the spring when temperatures warm.

resource

Strawberry Cultivation Guide

~Melissa Queen of Earth ♛