Plants produce energy for growth through photosynthesis and respiration. Both must happen in order for the plant to maintain health. Photosynthesis only occurs in the presence of light (carbon dioxide + water + light) creating glucose and oxygen. Respiration occurs all the time and especially at night. During respiration glucose sugars are broken down and energy is provided to the plant.
If plants do not receive the correct ratio of water to carbon dioxide and sunlight then glucose production is not maximized and plant growth slows, causing stress. Likewise, if the environment is not conducive to respiration then growth slows and stress increases. There must be a sufficient quantity of stored glucose in the plant for respiration to occur. Temperature plays an important role in this reaction.
Temperatures should be 10° -- 15°F cooler at night than during the day. If not then respiration can occur at a greater rate than photosynthesis. Another way to look at it would be the amount of glucose produced by photosynthesis is not enough to keep up with the amount of bonds broken down during respiration; effectively halting plant growth.
When transplanting plants it is important to create as little shock as possible. Plant quickly, use water and plant when it is not hot or windy. If plants are in a pot then soak the soil before transplanting. Dig the hole wider than the existing root mass of the plant being transplanted. Make sure the soil is loose and high in organic matter. Place the plant in the hole, cover firmly and water immediately. This will create the smallest amount of shock to a plant. If plants are received without soil, soak the roots in water if possible as you prepare the hole for planting and water as soon as you plant in soil.
One way to ensure healthy plants is to give them a healthy start. Don't wait to plant, plant in the proper environment and water immediately after planting, even if rain is in the forecast. Keeping plants stress free allows them to continue their cycle of photosynthesis and respiration producing lush and full plants.
The Extension office is open Monday - Friday, located in Kennett, Missouri at 101 South Main Street (the old bank) on the 2nd floor. For horticulture questions contact the horticulture specialist at 573-686-8064. MU is an equal opportunity/ADA institution.