Generally speaking, Bonsai trees are quite hearty and hard-to-kill. However, one of the exceptions to this is heat. Aside from a handful of breeds that come from high temperature climates, most Bonsai will start to suffer once temperatures get to around 90 Fahrenheit and frequent sustained highs over 100 degrees can become fatal.
And with climatologists predicting 2016 to be one of the hottest years yet on record, protecting your Bonsai from the heat may be a major issue this year.
So, we've got some suggestions for keeping them safe. This blog applies more to outdoor trees than indoor, obviously, although of course it's important to keep your indoor trees from getting too much direct sunlight during the hot summer months.
Important Tips For Keeping Your Bonsai Alive In The Summer
1 - Move the tree to a climate-controlled area if possible.
Even if your Bonsai is an outdoor tree most of the time, moving it indoors (or into a greenhouse) will probably be a good idea if you're in an area facing high summer temperatures. If this isn't possible, at least look to arrange for it to have more shade, even if that means giving your Bonsai its own beach umbrella for the summer.
2 - Water, water, water!
For outdoor trees in the summer, over-watering becomes a near impossibility. They'll need just about every drop they can get, and you will probably find yourself watering them at least three times a day: In the morning, when you get home from work\school, and before going to bed.
A good soil moisture meter can help here, since you might be surprised at just how quickly water evaporates from the soil during the summer.
3 - Use fine-spray misting for the leaves.
It's a good idea to keep leaves hydrated, as well as the soil, but there's a danger here: Standing droplets of water on leaves will act like magnifying glasses when the sun starts beating down. Rather than hydrating the leaves, the water droplets can outright burn them.
So use a spray bottle with a very fine mist, to ensure large droplets don't stick to the surface of leaves.
4 - Avoid nitrogen-heavy synthetic fertilizers.
They're harsh and bad for your soil in large quantities even in the best of times, but nitrogen-based fertilizers can be downright deadly in the summer. They require the tree use a lot of resources to process, and in the summer, the tree needs those resources to stay alive. (Kind of like how a heavy protein-rich lunch on hot days can make you feel sick.)
Stick to organic fertilizers, like compost-based products, or fertilizer blends made specifically for Bonsai.
5 - Spread moss around the bed.
If you're looking to be proactive -which is a good idea- now is a great time to plant moss around the base of your Bonsai tree. As we've mentioned before, moss is terrific for Bonsai, providing cooling insulation for the roots as well as holding in moisture. A layer of moss on top of your potting will do a lot to protect your tree from the ravages of summer.
6 - Watch the leaves carefully.
Most Bonsai show illness in their leaves first. If the leaves on your tree start looking yellowed - or worse, blackened - that's a major red flag that the heat is harming the tree. Do more watering, add more shade, or do whatever it takes to bring the tree inside until it can heal up. If the leaves are discolored, it's already in some trouble.
Need more advice? Please don't hesitate to contact the experts at BonsaiOutlet for more Bonsai health tips!