13 of us were treated to a fascinating talk by Darren Lerigo of Modern Mint on Saturday 7 May. The subject was water – its changing role in gardens and how we can better deal with having too little & too much. It was entertaining, informative and thought provoking.
Darren started with a few facts. The main uses of water are agriculture, business, cooling power plants, domestic, eco-system services, fluvial and gardening. Historically, most of our water has been used for agriculture, and that’s still the case in many countries – 92% in Iran for example (much of it used to irrigate crops exported to Europe). But in Europe the single largest use of water is for cooling power plants – likely to put our whole system under stress in years to come as our population increases, with resulting increased demand for water for agriculture, domestic use and gardening. Unless of course we switch to renewables, which don’t need cooling.
Water is predicted to be an increasing source of tension as the climate changes. In the UK, we are predicted to have hotter drier summer and wetter winters, so will have more droughts and more floods. This means we have to get cleverer at water management.
There’s a lot that we as gardeners can do to help deal with both drought and flood – at the same time as making life easier for ourselves. There were 2 main principles behind many of Darren’s tips:
• slowing rainwater down when it falls and
• steering it towards where you need it.
Ideas like green roofs, rainwater harvesting, rain gardens, permeable paving and swales (canals to direct water to where you want it – a pond, bog garden or a rain garden).
The use of water in gardens has changed over the centuries, from simple irrigation originally, to the great Arab gardeners using water to create a calm atmosphere and cool the air, then via naturalistic gardens and more austere modernist installations to the latest thing in garden design – rain gardens. These aim to reduce the stress on our overburdened sewer system (built 200 years ago for a much smaller city) by diverting water from your downpipe to a specially created small area filled with plants that can withstand being submerged for short periods. The water then percolates slowly into the system rather than all at once.
If you’d like to know more about rain gardens, try these: WWT rain garden leaflet and www.raingardens.info.
We learnt about good plants for rain gardens, specific tips for watering chilies and tomatoes and water-wise food plants (including some surprise popular ornamentals).
A further tip was for a Trading Hut favourite – seaweed fertiliser . A dilute solution sprayed onto leaves protects against a light frost.
How to do less watering
A question that Darren is often asked is how often or how much to water, to which the answer is “it depends” – on the plant itself, on the weather, on the soil. So the key thing is “observe, observe, observe”. But he did have a couple of specific tips.
- It’s not compulsory to have everything on your allotment or in your garden at the same level. If you plant (or sow) at a lower level, any watering stays right where you want it. So sow seeds in trenches and create a small hollow for plants.
- For pots, the key thing is to have as large a pot as possible. Darren also recommended using wool compost, which retains water for longer than other kinds.
Tips for specific plants
Chilli Bob & Chilli Neil say you need to stress a chili plant, so wait until it is wilting and then water thoroughly (once the plant is healthy, of course, you wouldn’t do this to seedlings).
“Treating them mean” is also a principle that works for tomatoes. But this time, instead of waiting for them to wilt, every 10 days or so, add a quarter of a soluble aspirin tablet to your watering can – the acid this creates stresses the plant and makes it produce sweeter tomatoes with higher vitamin content. Again, only on healthy and well established plants!
Water-wise crops
Or crops that need little watering. Darren recommended dahlias (whose tubers can be cooked & eaten like potatoes), figs, lavender, sea kale, spelt, pelargoniums, huckleberries, oyster leaves, pineapple guava, birch (whose leaves & twigs can be used for tea and wine), sedum leaves (sliced in a salad – apparently they taste like cucumber), pine leaves and hosta which can be used as a cut & come again salad leaf! there’s more on the Modern Mint blog here.
Key actions all gardeners should take to reduce the impact of drought or flood
• No watering at 2pm – if it’s a hot day, most of the water will evaporate before getting anywhere near the roots.
• Alleviate drying winds, using hedges or other windbreaks
• Mulch
• Reduce the lawn
• Buy locally grown flowers, to reduce your water footprint
• Use grey water in the garden
• Build a rain garden – please tell us if you do, it’d be great to share via this blog