Steve Edney & Louise Dowle: Propagation and Sowing Demonstration
Something of a regular appointment on our schedule, we welcomed back Steve Edney (our Patron) and Louise Dowle for an interactive talk that brought our best attendance for some time – people really have a thirst for expert, practical advice. And there was no shortage of that here. An additional feature of the evening was the annual charity Plant Sale. We had four tables of these, plus some early-season produce: rhubarb, leeks and asparagus.
They began with a ‘kit list’, comprising seed mix, vermiculite, perlite, some seed trays (they favour the smallest ones) and module cell trays; some propagators, the unheated kind. They do not favour the heated kind as they tend to be too hot for anything except exotics, although Gary Bradbury suggested using a plug timer so that the heat comes on intermittently. Steve and Lou do, however, use heat mats, which they feel are more versatile than propagators. When it comes to seed compost, they stressed that it should be sieved, using one with a medium-gauge mesh, to correct for the compaction that usually afflicts it from being stacked on pallets: seedlings need oxygen. Once in the seed tray it should be flattened and tamped down, not too firmly. And don’t over-sow; with very small seeds, mixing them with a little sand helps distribute them evenly. Cover with vermiculite, fine then coarser on top. This acts as a mulch, keeping the air/water balance right. Include date of sowing on labels. With bigger seeds such as beans and squashes, multi-purpose compost is fine to use. Be sure to use a fine rose when watering, or soak in a water tray – and warm up the water first!
Steve and Louise don’t sow much before April, with the exception of chillies. Plants will catch up once the weather gets warmer. Earlier sowings can result in spindly plants which can’t be safely planted outside.
They then moved to the next stage of growing plants: pricking out seedlings. You should handle them by one of the seed leaves, not the stems. Use a fine implement like a stick, a skewer or an old kitchen fork to use them out of the compost. When they are planted in their new medium, plant them deeply, almost up to the leaves: this makes for sturdier plants, which will not fall over when watered, and they will put out roots from the buried stems. Using module trays with large holes in the bottoms helps when it comes to pushing them out. The compost does not fall through. Watering is done best via a water tray, a mister or a small can with a very fine rose. You can also do foliar feeding, using liquid fertiliser such as Formulex in the water from a mister. This helps to avoid the problem of excess water retention with peat-free compost.
With cuttings, it is better to take them in the mornings or evenings, out of the strong sun. Water beforehand, e.g. the night before. They should also be kept in the shade until they are established. When taking them, put them in a plastic bag, to keep them from drying out. Rooting hormone is best in gel form rather than powder. This helps roots to form more quickly and strongly, but it won’t make roots form if the cutting has not been done correctly. Cut below a node and pinch off the lower leaves; look for slender stems. Salvias need a bigger, longer cutting – remove any flower buds. They can be cut longitudinally, to make extra plants quickly. With dahlias, basal cuttings can be taken now (late April), and must be solid, not tubular. Tubers can be divided, discarding any that have no neck or shoots emerging. Cut them apart with a good blade – a cheap breadknife will do – and pot them up. The growing mix for cuttings consists of a 50-50 mix of seed compost and perlite. Loam-based compost such as John Innes No. 3 retains moisture, so helps cut down on the need to water.
Cuttings planted around the edge of the pot seem to make roots more quickly, and doing this saves space, if you have a lot of cuttings. Cuttings are an especially useful propagation method for plants such as phlox, in case there are eelworms in the root system – dividing them simply spreads these around. Pelargonium cuttings should not be put in a propagator: their leaves need to have air circulating round them, otherwise they are liable to rot. Hostas will need to be divided – the breadknife will come in handy again – as they outgrow the pot. It’s best not to water the pot first: they divide more easily when not wet. Asters can be dealt with in a similar way, and will root quite readily. They can be divided at any time during the year, as can any member of the daisy family. Steve & Lou closed with some recommendations for further reading, should you wish to enhance your propagation expertise, referencing books by Jekka McVicar, John Cushnie and the RHS. And then it was time for Steve to present Esther Spanton with her delayed prize from the Spring Show.
