My flowers growing in hanging baskets have taken a real beating during recent hot weather. Even my tomato growing in a big pot does not have normal looking leaves. Is there anything I can do to help them?
There are things you can do to alleviate heat damage to a certain degree. However, heat is not your main problem. Container plants have special requirements that are somewhat different from those planted in the ground. Containers limit soil drainage, so container soils must be much more open and well drained. The coarse, irregular materials in container mixes contain more large holes than ordinary soil. These holes drain more quickly and provide the oxygen which all plant roots need. Because there is limited soil for the roots, they must be watered more often. In a 90-plus degree heat wave, once a day may not be enough for larger plants. Wilting leaves are a sure sign a plant needs water.
One way to help the plants is to give them more shade temporarily. Plants in full sun could be moved to where they get shade for part of the day. Plants in partial shade could be moved to full shade.
Fertilizing
I have found that a big part of deterioration of most container plants is a lack of adequate fertilizer. Frequent watering dissolves the nutrients in the soil and washes them out the drain holes of the pots. Even timed-release fertilizers like Osmocote start to become used up. I always fertilize all my container plants in early August. I make a second application to other plants based upon their appearance. An excessive number of yellow older leaves is a sure sign a plant is running low on nitrogen. Sweet corn always needs more nitrogen fertilizer now. Other long-term vegetables like squash and tomatoes often need more fertilizer. Purplish leaf color in tomatoes indicates a need for phosphorus. I will even put fertilizer on perennial flowers, especially newly planted ones that I want to encourage to grow larger and fill a certain space. A recently planted small tree or shrub could use some extra fertilizer about now.
Since lawn fertilizers contain a large amount of nitrogen, I use it for plants with yellow leaves. For phosphorus I would use super phosphate or a general purpose fertilizer such as 16-16-16.
