Propagators – The must have purchase this month!

If you want to raise your own plants from seed, an electrically heated propagator is a must.

In fact, it only uses as much electricity as a light bulb, yet it allows you to produce all your own tomato plants, as well as many veg and bedding plants. then there are houseplants and exotics. Invest in one and it will save you a fortune – and introduce you to a very satisfying new hobby.

Setting up

Stand the propagator on a windowsill or table close to a window where it gets good light but won’t be in strong midday sun later in the spring (which will cook everything inside). A small, inexpensive, heated propagator won’t be thermostatically controlled. It will be on all the time and capable of raising the temperature inside by approximately 10°F above the ambient temperature. So in a room that is normally heated to 60-65°F, the propagator will maintain the ideal temperature (70-75°F) for raising a wide range of useful plants.

Good hygiene is vital. Sterilise some silver sand (a small bag is enough) by transferring the contents into a plastic roasting bag and baking it in the oven for an hour on a very low setting. Allow to cool, then spread a layer around ½in deep all over the base of the propagator and dampen it slightly, so that it’s just moist. this is to spread the heat evenly and maintain humidity.

Have ready a supply of clean, plastic pots; square 2in pots make the best use of space. Stand them inside, empty, to check they will fit the propagator exactly, allowing the lid to close over them.

The day before you intend starting to use the propagator, plug in and switch on, to give it time to heat up and warm through. Close the ventilators in the lid to trap the heat inside.

Plan your sowing sequence

Aim to keep the propagator full all the time it is in use, to get full value for money from the electricity used. Plan a sequence of sowings, starting now with slow-growing seeds that need warmth plus an early start, such as houseplants, pelargoniums and greenhouse peppers and aubergines.

These should be ready to move out of the propagator in mid-March. Then you can re-use the space by sowing tomatoes, herbs and peppers or aubergines to grow out of doors. In mid- to late-April, you might try sowing cucumber and melon seeds – and also some courgettes, squashes and pumpkins so that you have plants ready to put outside after the last frosts have safely passed in late May. Mark sowing dates on your gardening calendar as a reminder.

Sowing seeds

Loosely fill each pot almost to the rim with multipurpose compost, strike it off level with the side of your hand, then tap down on a hard surface to settle the compost. press the surface down very lightly with the base of another clean, dry pot to firm it gently.

Sprinkle seeds thinly and evenly over the surface. very small seeds don’t need to be covered; they need light to germinate and are easily swamped. larger seeds (tomato seed-sized upwards) should be covered to their own depth with finely sifted seed compost. Insert a label in each pot with the name of the plant, the variety and the date of sowing.

Water in the seeds by standing the pots in an inch or two of tepid water until the change of colour shows that it has soaked through the compost. Allow excess water to drain away before placing the pots inside the propagator. when it’s full, close the lid.

Check the propagator daily, watering the sand in the base slightly if it becomes dry – this also helps keep the compost in the pots at the right moisture level. when seeds start germinating, open the ventilators in the lid of the propagator to allow air exchange to take place; open them fully as the seedlings develop, to deter fungal disease. then prick the seedlings out as soon as they are big enough to handle.

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