What a difference a month makes, both light and temperatures are increasing although don’t be caught out by the occasional frost. The seasons are generally the same each year, here in the North the chance of frost is still possible well into May, so protecting plants that have been started under glass is essential. There is little we can do about the new growth on trees, shrubs and other garden plants, some more susceptible than others. Last year we had a late frost which really nipped the hydrangeas and whilst they recovered it did set them back. Plants that are termed ‘hardy’ usually recover, but to help them along it is worth giving them a dressing of general fertiliser around the end of May. Most of the plants we buy or grow for summer bedding displays and indeed some vegetables are considered ‘half hardy’ which means they are quite happy growing outside providing there is no danger of frost, (usually after the end of May, in Yorkshire). These plants are grown from cuttings or seed in heated greenhouses and need to be hardened off before planting out.
Growing half hardy plants from seed is fairly straight forward but you will need either a heated greenhouse or a large propagator ideally with grow lights. Windowsill propagators are quite good but once the seedlings start to emerge they need good light and often grow spindly if lighting is poor. Bear in mind that at some point the young seedlings will need potting on and more space (and light), so inevitably a greenhouse is the ideal solution. Heating a greenhouse even just to give frost protection can be expensive, and is usually only for the most dedicated. In any case lining the greenhouse with either fleece or bubble insulation can help protect plants. Most commercial growers are sowing summer bedding plants early in the year which means that if you plan to copy that the greenhouse will need heating from early February until early May. Buying plants as plugs means that you avoid the need for early heating normally delivered around the end of March therefore the need to heat your greenhouse to give frost protection is only necessary for around eight weeks, after which the heating can be turned off to acclimatise the plants before planting out in late May.
If you do not have a greenhouse or indeed do not have the time to pamper and pot on seedlings and young plants, or if you are just starting out, then plants for summer bedding displays can be purchased from Garden Centres and Nurseries and providing you do not buy them too early can be planted directly into the garden or in containers. Don’t be tempted to buy before mid May as although they may seem quite robust they can still be damaged by late frost.
For those who only want a small patch of flowers or just want to fill gaps in the borders of trees and shrubs then it is worth considering sowing hardy annuals directly into the soil where you want them to flower. A little care preparing the soil by forking and breaking down to a crumbly structure similar to that of bagged potting compost, sow thinly in rows, cover lightly and water in, hardy annuals will happily germinate and can be replanted taking care not to damage the roots. The reason for sowing them in a row rather than just sprinkling over an area is that you can recognise a row of seedlings more easily, especially if there are weed seedlings germinating too. Protection from slugs may be necessary, copper tape barriers, beer traps and wildlife friendly slug tablets are available and are fairly effective.
It’s also a great time to repair the lawn by seeding bare patches, although it is a good time to be sowing seed, it’s also a time when birds are feeding their young and, yes they do like freshly sown grass seed. What I do is mix a handful of grass seed with three handfuls of potting compost or if you have some grow-bags from last year’s Tomato crop, crumble the compost into a bucket and use that. There is no need for fertiliser at this stage. A handful of seed will cover about a square metre (or sq yard) so its fairly easy to work out how much you need. Place the seed and compost mix into an empty compost sack, mix thoroughly and place in a frost free place, garage, or greenhouse. Check the contents every few days and once you see the seed starting to germinate, usually a small root about 2 – 3mm( 1/8th inch) then scratch the bare patch of lawn with a wire rake or fork, and sprinkle the seed/compost mix over the surface. Lightly rake in and water. The seed will root down quite quickly, and for some reason birds don’t seem to bother pre-germinated seed.
Happy Gardening.
Martin
Next month, ( tomatoes inside and out, time to prune plums and cherries, sowing root crops.)
