Crocus care tips for April
To plant or not to plant, when is the question!
There was a time when the gardening novice could time the planting out of tender bedding by watching to see when the groundsman of their local park planted up massed displays in beds and containers. Now though, so few parks are planted with summer bedding that this expertise and foolproof guide to the local climatic conditions is lost. Tender plants, like summer bedding and patio plants, cannot cope with freezing temperatures and cold winds, so they must not be planted outside until after the last frost in your garden. Even after this date you should be prepared with sheets of newspaper or gardening fleece to hand so that you can protect vulnerable plants on cold nights. If at all unsure, the best advice is to err on the side of caution and plant slightly late to avoid disaster.
Keep tabs on the local weather forecast, because the last frost dates can very dramatically from year to year. The altitude and exposure of your garden will also need to be taken into account. For example, the higher you are above sea level, the later the last frost is likely to be - sometimes as much as one week for every 50m. Bear in mind however that cool air sinks, so that the coldest areas are often at the bottom of valleys where the cold air is trapped (this is known as a frost pocket). On a much smaller scale, obstacles such as fences and walls in a sloping garden can trap cold air behind them causing a localised frost pocket. For this reason, you need to understand the microclimate in your garden, as it can vary even over very small distances. If you are new to gardening or have recently moved to a new garden, take the time to keep a record of which borders are first to get frosted as well as those that stay frost-free even on very cold nights.
Hardening-off plants
Now that few gardeners raise their own plants from seeds and cuttings, the essential practice of hardening-off is fast becoming a lost art. The technique is easy enough, you simply wean the plants gradually from the cosy environment that they have become accustomed, until they can cope with the harsher realities of life outside. All tender plants that have been grown inside (and even some fully hardy plants that have 'forced' by growers to sell in garden centres in early spring), need to be carefully hardened off before being planted outside - unless the supplier has already done this for you. If you are not sure, you'll need to allow about two weeks to harden-off the plants yourself at this time of the year. If you have a coldframe or greenhouse this is easy to achieve, by gradually increasing the amount of ventilation to improve airflow and slowly reduce the temperature. At first, ventilate during the day only, slowly increasing the time and amount of ventilation during the first week until you can leave the coldframe open on milder nights. During the second week, ventilate freely during the day and shut at night only if cold temperatures are forecast.
If you don't have any of these facilities, you can harden-off plants perfectly well in a sheltered corner of your garden (on a patio close to the wall of the house or under a hedge), once the last likely frost has passed. Cover the plants with a couple of layers of gardening fleece overnight and during cold or windy conditions, but remove it during the day if the weather is mild. As before, uncover the plants gradually over the following days until they are left completely unprotected on all but cold nights. If your garden is exposed to the wind then you will have to take extra care.
