It never rains – but it pours! Or, it simply just doesn’t rain! The great British weather is one of our favourite talking points, especially when we get it in extremes. You only have to think back to the last few summers and winters to appreciate how exceptionally variable these seasons can be – warmest winter and wettest, coldest summer and this summer almost the hottest on record.
For us gardeners, weather is extremely important, as it has a massive effect on our plants and gardens. And when there are extremes, and huge swings in weather conditions, our poor plants – who have to just sit and take whatever gets thrown at them – can suffer, showing signs of weather-induced stress in their growth, leaves, flowers and fruit.
The answer lies in the soil
A plant’s root system is so important, especially when it comes to taking up water. People only really think about what’s going on above ground – leaves and flowers. Yet, what’s going on in the soil is even more important. When roots get stressed, plants become stressed and that’s when everything starts to go downhill fast. Plants then become more susceptible to any poor growing and environmental conditions and pest and disease attacks. Look after the roots – and they’ll do a lot of the work to ensure the whole plant grows and flourishes for you.
But extremes of weather – especially drought and flooding/waterlogging (and that also includes you underwatering or overwatering) – can have very adverse effects on the roots, affecting the whole plant.
In drought conditions, there is no free water in the soil for the roots to absorb. As the plant needs water to live, it starts to shut down, stops growing, sheds fruit, flowers and leaves as an attempt to survive and, eventually, dies.
In waterlogged/flooding conditions, all the air spaces in the soil are full of water. As the roots of nearly all plants need air in the soil to live, they “suffocate” and die. This means no water for the rest of the plant – so it starts to shut down, stops growing and, eventually, dies. That’s why the symptoms of drought/underwatering are more-or-less the same as waterlogging/overwatering.
So, what can you do to help alleviate these issues?
Proper soil preparation is the key to your plants survival. Just “digging a hole and bunging it in” is not the way to get the best from your plants – especially in “poor” soils such as heavy clay, light sandy or stony soils and chalky soils.
Watch my video on planting container-grown shrubs
Bulky Organic Matter
Adding lots of bulky organic matter, such as garden compost, well-rotted manure, leaf-mould or composted bark or anything similar available in bulk, will improve all soils, especially poor ones. It improves the structure of clay soils, preventing them turning into concrete in summer and increases the water-holding capacity of light soils.
Whenever I’m asked to diagnose problems with sickly plants, it nearly always boils down to poor initial soil preparation. That’s why on BBC Radio Cambridgeshire they call me “Bulky Organic Matter Hodge” – at least, I think that’s why they call me that, rather than I always talk a load of manure!
Adding a good layer of organic material over the soil after planting (and whenever it needs topping up) will help keep the soil moist in summer. A “good layer” means a good depth. 7.5cm (3in) is a good depth, 10cm (4in) is often recommended, but I think a bit over the top. You’ll get some benefit from 5cm (2in), but anything less than this will have no effect at all. And always add your mulch to already moist soil – otherwise it will simply dry it out further.
Correct and proper watering as and when plants need it, and certainly before they start to shut down, is essential. You can find some advice on this in my previous blog and from Geoff Stonebanks on his article on watering containers Or watch my video here.
Some fertilisers and products you add to the soil at planting time can help produce a bigger, better root system that is better able to search out any source of available water. Funnily enough, Richard’s Root Booster is one of these!
Using plants that have developed numerous adaptations to a lack of soil moisture over the millennia is a great way to reduce the risk of everything dying in summer – and how much watering you have to do. But that doesn’t mean you have to fill your whole garden with cacti! There are loads of suitable plants, including those with silvery leaves, hairy leaves and succulent leaves.
Some of the things above that help when soil water is missing also assist when there’s far too much of it! Bulky organic matter improves the soil’s air capacity, as well as helping improve the structure and drainage of clay soils, helping to prevent them becoming a quagmire in winter. Mulches help waterlogged soils dry out in winter.
In extreme conditions, often the only way around regular waterlogging and flooding is to make a sump in low parts of the garden or even lay an underground drainage system. If neither of these are practical, then you may have to resort to creating a massive bog garden!