Gardens: the April checklist

http://www.theguardian.com/lifeandstyle/2015/mar/29/the-april-checklist-gardens-dan-pearson

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Late frost

Contrary to what you might imagine, sprinkling vulnerable plants with water the night before covers them in a protective layer of slightly warmer water if frost is threatening. Fleece blossom on wall-trained fruit if you are fearful, but remove it in the day so that the bees can do their work.

Sowing outside

As soon as soil is up to 6C, it is safe to sow hardy veg, such as broad beans, beetroot and early cut-and-come-again salad. The salad will race on if you have the benefit of cloches.

Sowing inside

Inside, and under cover, you will probably have already sown tomatoes and slower-growing half-hardy annuals, such as zinnia and pelargonium, but you can start annuals that need less time. Tagetes, courgettes and sweetcorn need about a month before they go out.

Sweetpea survey

Get the sweetpeas sown for a later crop. Plants already established in liners can be planted out safely. They like plenty of compost at the bottom of the trench, and twiggy support.

Pond life

Domestic ponds can look unsightly as matter at the bottom starts to decompose in warmer temperatures. Check that you don’t have tadpoles, and drain by a third to allow easy access for the removal of fallen leaves and excess plants. Waterlilies like to be re-potted every third year. Remove the strongest growth to the outside of the clump and replant in a good loam, not a peat-based compost, which will rise to the surface. Leave debris beside the pond for a day before composting to let any wildlife crawl back to water.

Revamping borders

Once you have cleared the borders, revitalise tired plants. Divide and replant in replenished ground where necessary. Never be afraid to change things. Stake now to avoid having to wade back into the beds once they are grown. If you have staked, weeded and mulched, you should only need to stray into the beds a couple of times more before autumn.

Perennial culinaries

Plant asparagus and strawberry crowns if you haven’t already, and split globe artichokes back to strong offsets if they are beginning to produce less.

Handling herbs

Leave Mediterranean herbs such as rosemary, thyme and sage until April to give them their prune. Clippings can be used as cutting material to keep short-lived plants in hand.

Dahlias

Plant dahlia tubers that have been stored inside into well-manured ground and if the weather warms this month remove any protective mulches you may have applied to those you left in the ground.