Ahhh, the great outdoors in the summer. What can you say about it other than “PHEW! It’s hot!”
Let’s take a look at what’s going on, why it’s so hot, what your bonsai needs at this time of year and finally, the real secrets of maintaining your bonsai through the summer.
There are two times of the year with extreme environmental conditions that you have to prepare for, and maintain thorough in order to keep your bonsai healthy, vibrant and ALIVE!
Winter and Summer.
We normally think of winter as the worst, but more trees probably die in the summer months than in the winter. The reason? It’s really hot! We’ll here in the South it’s hot anyway. Up North, it feels hot and can be stifling, but I’m sure there are places along the coasts where sea breezes keep it pleasurable. Still, for most of the country, it’s sweltering!
As you probably remember from 7th grade Earth Science (or the Discovery Channel) The Earth has rotated on it’s axis so that the sun’s rays are beating down upon us full force! That means, if it’s not overcast, almost every drop of water is going to be evaporated out of the top inches of ground and tree leaves and put into the air making it humid. In the Summer, there also seems to be less wind (where I live) and that makes one really sticky situation! Thank god for air conditioning!
Your trees have their own type of air conditioning. They circulate water as they evaporate it. Imagine cool water from the ground coming up through the roots, into the trunk and out to the leaves. The water goes from very cool, almost cold in the ground to hot by the time it reaches the leaves. This happens up to 90 degrees. At 90 Degrees, the stomata (the little pores) on the leaves of plants close to protect the plant and retain moisture.
That’s how “regular” trees in the ground do it – but what about your bonsai? Let’s compare.
When a tree is in a pot (bonsai) then the access to plenty of cool ground water is limited. That means it has less access to water.
Think about that. With less access to cool water, a bonsai has less ability to cool itself and adjust to varying conditions.
What this means is, leaf curl and leaf browning due to the heat. If a bonsai is not taken care of daily during this time of year, the leaves will completely die and fall off, and then the plant will die rather quickly.
So, what are the secrets to taking care of your bonsai during the summer? Water, fertilizer, and shade.
First, you can’t water enough in the summer! Ok, well, you can water too much anytime of the year, but that depends on your soil. If you have used potting soil (tsk, tsk) then all that peat moss is going to hold water – and attract fungus, then fungus gnats, and then spiders to eat the gnats, and all manner of other insects – see why we suggest porous, well draining soil?
So, water, water, water! Up to a maximum of 5 times a day. Ideally you will water before you leave for work, water the minute you get home, and check them again before you retire for the night. Your job in the summer is to make sure your little trees have all the water they can use.
Proper nutrition ensures we grow to our full potential. Your plants are the same. When you give your plants a healthy amount of the beneficial nutrients, vitamins and minerals that they need to grow, they will grow strong, healthy, and beautiful. In the summer, you should water your bonsai at 3 / 4 to full strength fertilizer once a week, or make a 7 times diluted version and use it every time you water in a constant feed (1 gallon full strength makes 7 gallons constant feed).
Finally, shade. Some species of plants will not do well in shade – like Junipers – so research your plant some. But other plants, like maples and azaleas could use some shade in the summer. The thing to remember is full shade is not good. What bonsai need is a portion of the day in full sun and a portion in shade. If you have a choice, then morning sun and afternoon shade would be ideal. But, the reverse would work. So if possible, put your bonsai on the Eastern side of your house, or against the Eastern side of a wall.
Well, there you have it! Now you know exactly why your bonsai’s leaves are curling up and turning brown and what to do about it. You also know what you need to do to keep your bonsai healthy and happy through the summer. It all comes down to the laws of nature vs. the desire of man. If you want a beautiful bonsai, you will have to protect it and simulate nature as much as possible. Just remember, water, fertilizer and shade.