Houseplant Propagation Equipment

Propagating plants is easy, provided you have the right equipment and follow a few simple rules. Here is the basic information you need, to help you get started.

In nature, there is no propagating equipment, because wild plants have exactly the conditions they need to reproduce. House plants, which may originate in tropical forests or deserts, often need a bit of help.

A prohouseplant-propagatorpagator provides the best possible conditions in which most house plant seeds can germinate and cuttings can send out roots. High humidity is especially important for many cuttings, which are liable to wilt and shrivel before their stems have time to form roots. (Cacti and succulents are exceptions, because their fleshy growth rots in damp air.)

Moderate heat helps speed up germination and rooting. A steady temperature is also important, especially in winter, when temperatures fall sharply at night. ‘Bottom’ heat is supplied from the base of electric propagators, and heats the compost and then the air. ‘Bottom heat’ is particularly helpful for rooting cuttings.

Accessories

As well as a propagator, the following are useful.

  • Seed and cutting composts have light, open textures, to retain moisture but prevent waterlogging. They contain little or no nutrients, which scorch young roots. Most are made of various proportions of peat moss, sphagnum moss, sand and vermiculite or perlite.
  • Hormone rooting preparations include powders and gels containing chemicals to encourage root production, and are very useful for hard, woody cuttings. Plastic trays or half trays let you remove young plants from the propagator without root disturbance, and quickly re-use the propagator for the next batch of seeds or cuttings.
  • Small flower pots and mini-pots serve the same purpose. Square ones make maximum use of propagator space. Gravel or moist peat is used to make a bed on which to place the trays, to distribute the heat evenly.
  • Hand misters increase the moisture content of the compost or atmosphere without the risk of overwatering.

Which propagator?

Propagators range from seed trays 21.5 x 15cm (81/2 x 6 inches), 5cm (1 inches) deep, with fitted lids, to mammoth, mini-greenhouse types 100 x 45 x 62cm (39 x 18 x 24 inches), with metal frame and sliding doors. Some large types are sold only in kit form. Decide where the propagator will go, and how many and what types of plant you want to propagate. Cuttings often need more height than seedlings.

Propagators with drainage holes are often placed on capillary matting so that watering can be carried out from below, but you can water them from above. Propagators without drainage holes are lined with gravel or peat to distribute the heat, and seed trays or pots are placed on top.

Unheated propagators are inexpensive, and are fine for most plants, especially when used in summer or in a warm room. These are made of an opaque, shallow, polythene tray with a transparent polythene top. Choose one with adjustable vents, although you can prop the lid open with a pencil if you have a simpler propagator.

Heated propagators are electrically warmed, with 12W, 14W, 20W, 24W, 50W or 65W elements. The simplest ones have a straightforward ‘on’ or ‘off control. Many have thermostatic control, for adjusting the temperature, from 7-30°C (45-85°F), and this type is preferable. Some have flat lids, others have ridged lids to accommodate tall cuttings and to allow condensation to run down the sides and into the compost. Some have flexible polythene covers over rigid wire frames. Some have visible cables while others have hidden elements.

Mini-propagators consist of simple plastic lids which fit over single flower pots.

Using your propagator

Make sure the compost is evenly spread and level. You can use a wooden firmer or your fingers; pay special attention to the sides and corners of the tray. The finished compost level should be 6-13mm (¼–Ve inches) below the rim. Before sowing or planting, water with a fine-rosed watering can, then allow to drain.

Sowing seeds

Sow thinly and cover with a layer of compost equal to the thickness of the seed; don’t cover tiny seeds. Keep shaded until the seedlings appear, then gradually increase the light levels and ventilate the seeds daily.

  • If you are sowing several types of seed, label the propagator with the plant’s name, and the sowing date.
  • Small square pots fit snugly together to make the best use of space.
  • More sophisticated propagators have a ventilation control that enables you to regulate the air intake very easily.

Taking cuttings

Take cuttings (see posts on individual plant for lengths) and remove the bottom leaves. Make a hole with a dibber or pencil, then insert the stem into the compost. Firm round the base of each cutting. New growth is usually a sign that roots have formed; double check by tugging the plant very gently.

CHECKLIST

DO

  • Follow the temperature guide given on seed packets. Use suitable compost, and sow thinly and shallowly,
  • Choose healthy, short-jointed shoots for cuttings and reinoye the lower leaves.
  • Wait until early spring helore sowing seeds of summer patio or balcony plants, or they’ll be ready for transplanting before the weather is warm enough.

DON’T

  • Leave the propagator in direct sunlight, or the young plants are liable to roast! Start many more seeds or cuttings than you have room to raise and display, unless you have firm homes for them first.
  • Let seedlings or cuttings come into contact with the lid of the propagator, or they may be permanently deformed or otherwise damaged.

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