I just spent some weeks in the Veneto, the area north of Venice, the hills packed against the Dolomites where the Prosecco comes from. I love this region as it is always green and lush. The reason for this being the almost daily thunderstorms that occur during the summer months. Many nights I lay in bed listing to the wonderful sound of rain, thinking guiltily of our garden struggling in the drought. Back in Berlin, one sees the effects of the prolonged summer drought. At the end of May I already wrote a (German) blog about gardening in the dry weather. Since then we have had little rain to speak of in Berlin and elsewhere in Northern Europe. News of fires, images of brown lawns and stunted crops have become part of the daily news.
I have on the one hand been surprised that the central road verges are still green-ish. The odd thunderstorm seems to have been just sufficient to keep the grass ticking over, but is not helping larger trees and shrubs whose roots are sitting deeper so they need more intensive watering over a longer period of time. Precisely these large plants are worth making an effort to preserve. They take more effort and time to replace and they do play such an important role in making urban life so much more bearable precisely in this heat. The humidity they transpire reduces the air temperature beneath them by several degrees and they absorb noise and dust.
What you can do
Authorities are asking people to help them by giving a few buckets of water to their street trees once or twice a week. Especially for relatively young trees (even those that have been there 5 to 10 years) it is important as their root network will not have reached very far yet. Also stressed plants fighting with disease or insect pests are in need of some extra tender love and care.
Regardless of what you are watering, check whether it was enough. Lift plants in pots or take one out of its pot, to see if the rootball is really wet: all too often only a centimetre or so is wet.
In beds and borders the most effective way is to water once, maximum twice a week thoroughly. We have increased our occasional watering from when plants show signs of thirst, to watering twice a week in the early hours of the morning for 30 minutes. We have planted quite a few new plants this spring, and watering them individually would be too much work.
Scratch a little in the earth, to check that the water has done more than wet the surface. Most effective is a light fine “rain” nozzle, held close to the soil surface where possible. Watering over head is not a deadly sin as long as you do not do it every day and avoid the height of the heat. (If it rains, the plants get watered on from above as well after all!). Where the soil is very dry, wet it a little, move on to the next area and go back after five or ten minutes and repeat.
The lawn is probably the least important area to worry about, even though it is always the first part of the garden to show serious signs of water stress. During hot weather you should set the blades higher so as not to mow as shortly as normally, and where possible leave the clippings as mulch. If you want to keep your lawn green, water once, maximum twice a week. Place a glass or other container on the lawn and let the sprinkler run long enough till 2cm of water have collected: this is the equivalent of 20l water, and enough to filter down to root level.
How best to water pot plants
Make sure your pot plants have saucers: particularly for smaller plants it is helpful during hot days to soak up any extra water. They may need watering more than once a day. Check, and if necessary do water during the daytime by plunging the pot in a bucket of water. they will retain some water
Can I plant in this weather?
For those of you who were away on holiday and have come back to beds and borders in need of a little face-lift and would love to plant a few new plants, you should give them the best start possible:
- Before planting, submerge the pot in a bucket of water until no air escapes anymore;
- Dig a generous hole, adding at least the same volume of compost as the rootball of the plant and mycorrhiza (these will help to supply extra water to your plants, as soon as the fungal mycelia have made contact with the plant roots);
- Flood the hole with water, let it soak away, then fill again before putting in the plant;
- Fill the hole and water in once more.
Check your fruit trees: some are so heavily laden that branches are breaking off. Don’t be too greedy and remove some of the fruit to reduce the weight and reduce the water demand.