gardening in climate change
Kelvin Mason gave an interesting and informative talk in July to the Titchfield Gardeners’ Club. Kelvin has 50 years horticulture experience and is a part-time teacher at Sparsholt College.
Kelvin’s talk covered the effects climate change is having, and what we can do to cope with the impact. In particular, Kelvin stressed that we should not leave ‘a mess’ for future generations.
We are currently in a drought year and 7 out of 10 years recently have been drought years as far as plants are concerned. It is predicted we’ll get wetter, milder winters over shorter periods. Overall, the temperature is rising, although this does not necessarily mean more sunshine.
The impact of the milder winters on fruits is significant. Fruits get less flowers if there is not enough cold during the winter as the plants need sufficient chilling to blossom. Less flowers will mean less fruits; this particularly effects apples, strawberries and blackcurrants.
What can we do to reduce the impacts of climate change?
Soil is the largest worldwide storage of carbon. We need more carbon in the soil. Add organic matter, which is a ‘magic substance’ that will keep moisture in the soil, (especially manure – more nutrients or leaf mould – less nutrients). Ideally, then cover the organically fed soil by adding a mulch or fabric (available from garden centres). Covering the soil reduces evaporation as well as keeping weeds down.
Kelvin also advised using a ‘no-dig’ approach during the warmest part of summer to keep the moisture in, as turning the soil increases the chance of evaporation and encourages loss of carbon as carbon dioxide. He mentioned Charles Dowding as an advocate of this with many publications.
Add organic matter to the soil in spring. Avoid doing this during the autumn as the heavy winter rain washes the nitrogen and potash out of the soil.
Plant to avoid bare soil, and hence, reduce the risk of evaporation. Grow “green manure” plants to avoid bare soil, especially over winter.
Layer plants (eg ground cover / herbaceous plants / Shrubs / trees all overlapping) so that they bloom separately, cover the soil and slow rainwater percolation through the layers into the soil, reducing the rate of run-off so that plants can slowly absorb more water.
Kelvin talked about phosphate fertilizers and advised there are no local sources for these: all will have travelled long distances. Also, an impact of the Russia / Ukraine situation is that hydrogen and nitrogen fertilizers are very expensive. Kelvin suggested using spent compost. Whilst it may not be as effective as some other fertilizers, it is ok to use alongside other organic matter.
Make compost at home and put your own home-grown nutrition back into the soil. For best effects, chop up prunings and other green garden waste and mix it up rather than layer it; then cover it. Doing this will mean it composts quicker. If you are lucky enough to be able to access horse manure, this is a very good activator and will speed up composting. Nettles will also help as an activator.
Water collection / re-use;
Use water butts (with lids) to collect rainwater. Save it and use it for plants but use tap water for seedlings to reduce “damping-off”. Kelvin added that rainwater is ok for ALL plants even though it is slightly acidic.
Only water early morning or evening this time of year to reduce the chance of evaporation.
Grey water (from washing up / showers etc) can be used on plants but avoid strong detergents and dishwasher water with high salt softener and don’t use hot water on lawns or plants as it can kill grass / plants.
Don’t waste water on lawns as grass will recover. Use it on plants.
Irrigation ‘drip’ systems / “leaky pipes” can work well by delivering water to the plant roots but avoid sprinkler systems as most of the water is lost in evaporation.
Garden Design considerations;
1) Roof gardens are good. Choose plants that don’t have a high demand for water - sedums are a good
example. Beware the weight involved!
2) Reduce the amount of hard landscaping as this can lead to flooding and waste precious water.
Consider block paving with gaps / pea-shingle
3) Rain Garden / Bog garden / gravel garden / “Swale” to slow water run-off+/- water loving plants to
delay / absorb water run-off / reduce flooding.