Garden lovers Gardening and landscaping 3 Steps for Sowing Under a Frame

3 Steps for Sowing Under a Frame

3 Steps for Sowing under a frame

3 Steps for Sowing Under a Frame



    – Calendar for sowing under a frame

    – Step 1: Choose between cold or warm frames

    – Step 2: Sow your seedlings in a greenhouse

    – Step 3: Monitor the germination and growth of your seedlings under a frame

A growing frame consists of a wooden box covered with a transparent sloping roof that you can easily lift. At night, it allows to gain a few degrees compared to the outside temperature; during the day, the sun rays hitting the glass roof raise the temperature considerably. Thanks to these special conditions, sowing can be brought forward by several weeks, making it possible to bring vegetable harvests or to sow flowers from January onwards. In addition, the frame protects the seedlings from bad weather and predators.

This post gives you all the advice you need to sow under a frame.

Calendar for sowing under a frame

Vegetable underframe

Here is the calendar for sowing under the frame for the main vegetables:

    – January: broccoli, carrots, lettuce, turnips, smooth and round peas, radishes.

    – February: broccoli, carrots, celeriac, cauliflower, lettuce, turnips, smooth or round peas, peppers, leeks, peppers, radishes, and tomatoes.

    – March: eggplant, broccoli, carrots, celery sticks, celeriac, cauliflower, cucumbers, gherkins, lettuce, melons, turnips, leeks, peppers, radishes, tomatoes.

    – April: eggplant, celery, celery root, Brussels sprouts, cauliflower, cucumbers, gherkins, zucchini, melons, peppers, radishes, tomatoes.

    – October: carrots, cauliflower, lettuce, radishes.

    – November: carrots, cabbage, cauliflower, lettuce, onions, radishes.

    – December: broccoli, carrots, cabbage, cauliflower, lettuce, early peas, leeks, radishes.

Necessary: before April-May, depending on your region, the sowing of cold vegetables (eggplants, cucumbers, gherkins, zucchinis, peppers, tomatoes) should be done under a warm frame.

Flowers underframe

Here is the calendar for sowing the most common flowers under frame:

    – January: ageratums, begonias, geraniums, impatiens, lobelias.

    – February: ageratums, begonias, dahlias, gazanias, geraniums, impatiens, lobelias, petunias.

    – March: ageratums, begonias, dahlias, gazanias, geraniums, impatiens, lobelias, Chinese carnations, Indian carnations, petunias, primroses, ornamental salvia, daisy pompons.

    – April: ageratums, Chinese carnations, lobelias, Indian carnations, petunias, primroses, daisy queens, ornamental salvia.

    – December: begonias, geraniums.

Important: flower seedlings should be sown in a warm frame before April.

1. Choose between cold and warm frames

Many vegetables can be sown in an unheated or “cold frame“.

However, from January to February-March, depending on your region, flowers and some cold vegetables need to be sown in exceptionally mild conditions, under “hot frames”:

    – Traditionally, a warm layer was made by placing manure under the soil: as it decomposed, the manure released heat.

    – More simply, you can heat your frame by installing an electric heating cable to be buried in the soil. However, stop the heating as soon as the seeds have emerged to avoid a too fast development followed by a withering of the seedlings.

2. Sow your seeds in a frame

Sowing Under a Frame

    – Place the frame in a sheltered area on the ground that has been weeded, spaded, scraped and raked.

    – Turn the lower part of the frame towards the south to heat it as much as possible.

    – Fill the frame with a thick layer of special potting soil or finely sifted soil lightened with sand and peat to avoid excess humidity that could lead to rotting and melting of the seedlings.

    – Sow your seeds in the usual way: in rows in light furrows, broadcasting or clusters for larger seeds.

    – Bring some soil over the seeds, except for begonias, impatiens and petunias, which need light to germinate.

    – Pack the soil lightly with a board.

    – Water moderately in a gentle rain after sowing.

3. Monitor the germination and growth of your seedlings in a greenhouse

    – Water your seedlings regularly, but not excessively, to prevent the seedlings from melting.

    – Protect the frame: at the beginning of winter or when frost is forecasted, cover the frame during the night using a straw roll, a winter veil or even an old carpet.

    – Aerate the frame: on sunny and milder days, open the frame to release moisture and avoid heat stroke that could ruin your seedlings. Don’t forget to close the frame at night.

    – When the first 3-4 leaves appear, thin out your seedlings by eliminating stunted or poorly placed seedlings.

    – Grow radishes in the field until harvest, but transplant other vegetables in pots or directly into the field when the vigour of the young plants allows it.

Equipment needed for seedlings underframe

Watering can with head







Potting soil


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