When you cut summer flowers for indoor display, do so during a cool part of the day and put them in water as quickly as possible. Remove any foliage that will be under the water in the vase. Keep your arrangements in a cool room out of direct sunlight. Adding a preservative to the water can lengthen the life of the flowers.
If you want to maximize the size of individual dahlia flowers, keep the main stems free of side shoots. This will allow only the terminal bud to develop, resulting in one flower per stem, at the expense of more but smaller flowers. This will be most effective when growing the large dinner-plate-sized cultivars. The plants will need staking to prevent wind damage and to keep the stems from breaking under the weight of the flower.
Bearded iris can be divided and replanted after they have finished blooming. Be sure to discard any shriveled or diseased parts, and be careful not to plant the new sections too deeply.
Keep the following general rules in mind when harvesting most vegetable crops:
Harvest vegetables at the peak of their flavor. Younger leaves and fruits are often more tender than those left on the plant longer. The length of time vegetables remain edible depends on weather conditions. High temperatures hasten maturity.
Check the garden daily and remove any ripe, damaged or misshapen fruits.
Handle vegetables carefully during harvest time. Fruits that are not easily removed from the plant, such as eggplant, should be cut with a knife.
Harvest on a regular basis to encourage production. Many plants, such as cucumbers, okra and zucchini, will stop making new fruit if mature fruits are not harvested.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.