Water Advice
Here’s some water advice from the RHS (extracted from their May Journal). Whilst most of us follow these tips anyway – but it’s nice to have horticultural justification!
Water use in times of drought
Strategies and methods for coping with drought fall into 3 main categories: water storage and irrigation, soil preparation and management and choice of plants
Water storage and irrigation strategies
Store water for dry spells: collect rainwater from roofs in waterbutts (this
also saves fetching and carrying the extra distance from a tap). Water
thoroughly every 7 – 10 days rather than little and often. Light watering can
be counter-productive: it may not reach the depth at which most roots are found,
and encourages surface roots which are most at risk of drying out.
Water in the cool of the evening or early morning. Evaporation rates are much
reduced.
Two further points not in the article, but which I am sure the RHS would endorse
Root Watering: sink 5 – 8 cm pipes or plastic drink bottle with the bottoms
cut off in the soil alongside plants that might need water eg strawberries grown
on black plastic raised mounds, eg between climbing French beans Water planting
holes while planting plantlets, and seed trenches before sowing seeds, in order
to reduce evaporation rates.
Soil Management
The amount of water a soil can hold depends on its constituents and
structure. Clay soils [I think this is the basis of our allotments’ soil –
please correct me if this is not the case] can typically hold around 105mm of
rainfall in the top 60 cm. It is possible both to increase a soil’s
water-holding capacity, and slow the rate of water loss by evaporation. Dig in
organic matter: this can increase moisture-holding capacity by the equivalent of
up to 50 mm of rainfall in the first year after application – enough to supply
plants for around 20 days. Mulch heavily: a 7 cm layer of chipped bark, green
waste or garden compost spread onto moist soil reduces evaporation and
discourages weeds. Remove weeds promptly as they appear, as they suck water out
of the soil. Stop digging or cultivating soil by late March if possible, and hoe
only to remove weeds, as both increase soil evaporation. This obviously means
advance preparation and clearly doesn’t apply to preparing the ground for
follow on crops.
Don’t walk on wet., heavy soils in winter: it can cause compaction, damaging
the structure and lowering the moisture-holding capacity
Growing Strategies
Delay planting perennials, eg fruit bushes, until autumn when water is more available: planted now they will need irrigation all summer. Choose more drought-tolerant varieties if available. Carrots, parsnips and cabbages can get by on less water than salad leaves, tomatoes, courgettes, cauliflowers and peas. Pumpkins and sweetcorn have the lowest requirements for irrigation water
