How to succeed in sowing sweet peas - Tutorial

When to sow sweet peas?

You can sow your sweet peas either indoors, in an unheated shelter, or directly in the open ground. The ideal timing varies depending on the method used.

• Forced sowing indoors

Sow in March to transplant the seedlings into the garden when the risk of severe frost has passed. An intermediate transplanting may be necessary. Place your sowings indoors on a well-exposed windowsill, in a cool room, and do not let the potting soil dry out.

• Sowing in an unheated shelter

Sow in October-November and winter your sowings under a frame or in an unheated greenhouse. Ventilate as much as possible. You can also sow in March. However, note that sowing before winter allows for stronger plants and earlier flowers.

• Sowing in the open ground

Sow your sweet peas directly in place, in March-April.

In regions with mild winters, spontaneous sowings are not uncommon in autumn, and the seedlings can winter without issue. If this is the case for you, you can carry out your sowings in late summer or early autumn and transplant them into the garden right away.

Soaking seeds

Sweet pea seeds often have an outer coating (the integument) that makes them difficult to germinate. To soften this integument, you can:

• either soak your seeds in warm water overnight before sowing.

Soaking sweet pea seeds.

• or take an airtight container. Line it with a damp cloth, then place your seeds on top. Fold the damp cloth over them. Close it and leave at room temperature.

Seeds are placed to germinate in a damp cloth; after 3 days, germination begins.

The seeds will swell, allowing them to germinate faster and better. When the seeds start to germinate, you can sow them!

For tough seeds that resist these treatments, chip the integument at the eye (small round scar) with a cutter to facilitate moisture entry and stimulate germination… which occurs a few days later.

Soaking is of course not mandatory, but it greatly speeds up the germination process.

Seed soaking: before/after

Sowing in buckets and other containers

You can sow your sweet peas in buckets. Sweet peas develop a deep root that can be hindered in a container that is too shallow, so if you have the equipment, ideally use “rootrainers” or biodegradable tubes, or even recycle toilet paper rolls.

• Sowing in buckets

– Step 1: Fill your buckets with good potting soil.
– Step 2: Place 5 seeds and push them down 2 to 3 cm with your finger.

Fill your buckets with potting soil and place your sweet pea seeds.

– Step 3: Cover the holes with potting soil.
– Step 4: Water.

Push the seeds down and water gently.

– Step 5: Cover (with a transparent lid, paper…) to retain moisture, warmth, and allow light to pass through.

Emergence of sweet pea seeds in buckets (Simon Edge-Flickr)

• Sowing in rootrainers

Sowing poppies in rootrainers (Peganum-Flickr)

– Step 1: Fill each compartment with potting soil.
– Step 2: Place 1 to 2 seeds on the surface of the potting soil in each pot and push them down 2 to 3 cm with your finger.
– Step 3: Cover them with a bit of potting soil.
– Step 4: Water.
– Step 5: Cover with the lid.

• Sowing in tubes or toilet paper rolls

– Step 1: Stand your rolls upright in a sealed container and fill them with potting soil.
– Step 2: Place 1 to 2 seeds in each roll and push them down 2 to 3 cm with your finger.
– Step 3: Cover with a bit of potting soil.
– Step 4: Water.
– Step 5: Cover.

Sowing sweet peas in toilet paper rolls (historyanorak-Flickr)

When the seedlings appear, keep them cool at around 5°C. This encourages root growth rather than stem growth. A cold greenhouse or a frame is ideal.

When the roots have filled the containers, it’s time for an intermediate transplanting, into slightly larger pots (if you cannot yet plant outside) or to plant in the garden.

Finally, it is also possible to sow your seeds in small Fertiss growing blocks, which are very easy to use and can be transplanted later. Olivier explains everything in the video.

Sowing in open ground

Sowing directly in the ground requires some preliminary work:

– Prepare the ground. For this, use a broadfork or, if unavailable, push a spading fork into the soil, lifting slightly to loosen the soil without turning it over.
– Remove large stones and unwanted herbs.
– Level the soil with a rake.

Remove unwanted herbs and stones.

Next, you can choose to sow your sweet peas in clusters or in rows.

• Sowing in clusters

This technique is perfect for sowing at the base of a support (trellis, arch, pyramid, dead tree, etc.). To sow in clusters:

– Step 1: Dig small holes 2 to 3 cm deep with a hoe. Space the clusters 25 to 30 cm apart.
– Step 2: Sow 4 to 5 seeds in each cluster.

Dig the clusters / Sow 4 to 5 seeds per cluster

– Step 3: Cover the holes.
– Step 4: Water.

You can place a piece of mesh over your sowings to protect them from scratching by cats or chickens.

Piece of mesh to protect the sowings.

– Step 5: After germination, thin out by keeping only 2 or 3 strong seedlings per cluster.

Germination of sweet peas directly in the ground (WxMom-Flickr)

• Sowing in rows

It is possible to sow in rows, in a vegetable garden, between two ranks of vegetables, for example. To sow in rows:

– Step 1: Use a string line and trace a furrow 2 to 3 cm deep.
– Step 2: Sow 1 seed every 5 to 10 cm.
– Step 3: Cover the furrow.
– Step 4: Water.

You can also make several rows spaced 40 cm apart.

Sowing sweet peas in a planter, pot or container

If you don’t have a garden, you can sow your seeds in planters or pots. To do this:

– Step 1: Place a layer of 2 to 5 cm of clay balls at the bottom.

– Step 2: Fill the pot with a mixture of half garden soil and a good potting soil.

Place a layer of clay balls and then fill with a mixture of potting soil and garden soil.

– Step 3: Sow the seeds, spacing them 15 cm apart. – Step 4: Push the seeds down with your finger to a depth of 2-3 cm.

Sow your seeds, pushing them down by 2 or 3 cm. Immediately place a support for the seedlings to climb.

– Step 5: Cover with a little potting soil. – Step 6: Water gently and then install a stake.

Always keep the substrate moist (not waterlogged).

→ Find our advice sheet: How to grow sweet peas in pots?