We turned to Tomatomania's Scott Daigre, author of the book Tomatomania!: A Fresh Approach to Celebrating Tomatoes in the Garden and in the Kitchen, who says “six to eight hours of sun [a day] is all a tomato plant needs so shade accordingly.” “The plant needs shade for developing fruit.
But most often, you'll need a system for shading tomatoes during a heat wave, or regularly during midday (10 AM – 2 PM) in the height of mid-season and thereafter, because that's when the sun is most intense and temperatures are highest.
Tomatoes are vigorous growers that require maximum sun. They will need 6 to 8 hours of sun a day, so plant in the sunniest parts of your garden.
Tomato Sunscald: Why Too Much Sun Can Be Hazardous to Your Tomatoes' Health. Tomato sunscald is a problem caused by growing conditions – specifically intense, direct sunlight for extended periods during very hot weather. The excessive sunlight discolors patches on ripening or green tomatoes.
Tomato plants ideally need at least six to eight hours of darkness per day to properly absorb carbon dioxide and work through the dark cycle of energy production.
If I keep plants under lights for 24 hours a day, will they grow faster? A. No. Tomato plants need at least 6-8 hours of darkness each day.
Porch lights can alter a plant's normal growth pattern by exposing the plant to more light than it should be receiving. Porch and outdoor lights will affect plants by exposing them to an unnatural quantity of light. Increased lighting periods cause plants to produce growth hormones as a natural response.
Early in the growing season, watering plants daily in the morning. As temperatures increase, you might need to water tomato plants twice a day. Garden tomatoes typically require 1-2 inches of water a week. Tomato plants grown in containers need more water than garden tomatoes.
Daytime temperatures consistently above 90° F or night time temperatures consistently above 75° F create all kinds of stress for tomato plants. It's too hot for tomatoes to be pollinated. That means fewer fruit. But even more worrisome is the toll the heat takes on the plants.
Tomatoes needs at least 8 hours a day of sunlight to produce fruit, but aim to provide 12 -16 hours of light for the best growing results. Tomato plants are day-neutral, meaning that they will flower independently of the day length.
Choose a sunny, sheltered spot, where you can plant them into a border (into soil that has had plenty of well-rotted garden compost added), or into 30cm pots, or put two or three plants in a growing bag. If growing tomatoes in a greenhouse, try growing alongside basil, which thrives in the same conditions.
If your plants don't get enough sunlight, you may find that they grow tall to reach for more sunlight, but never produce any fruit. Tomato plants that don't get enough sun might grow tall when trying to reach for the light. However, they might not produce any fruit!
Unfortunately, shading limits the light plants receive. As plant growth depends on light, only the minimum amount of shading should be used to keep temperatures below about 25-27ºC (77-81ºF). Otherwise, allow as much light in as possible, particularly when growing edible plants such as tomatoes.
Use a Cover to Protect Tomatoes
When frost or temperatures are in the forecast for overnight (mid-30s or even 40ºF), cover your tomato plants with clear plastic or a tarp. If you face an extended cold pattern, consider using quality frost protection regularly.
Also, watering tomatoes early in the day cuts down on evaporation, so plants stay hydrated longer. Some gardeners make a strong case for watering in the middle of the day. Midday heat and sun help leaves dry quickly, which increases humidity around plants and cools the leaves.
Tomatoes are sun-lovers and require full sun, which means that they need unobstructed, direct sunlight for 6-8 hours a day, no cheating or skipping.
The best time to water your tomatoes is early in the morning. This will allow any moisture that makes its way to the leaves an opportunity to dry before the heat of the day, and that can help to prevent diseases and burning of the plants. You need the water you're administering to be efficiently used.
Tomato plants die when the temperature goes below the 32 degrees Fahrenheit (0 degrees Celsius) mark.
Coffee grounds contain around 2% nitrogen as well as varying amounts of phosphorus and potassium which are all very important for the growth of tomato plants. By mixing some coffee grounds into the soil below your tomato plants you're introducing these nutrients that the plants need to thrive.
One part of the plant showed significant leaf curl because the growing point of this part of the plant was accidentally removed. As long as there are other growing points remaining, the plant can recover, and the leaf curling will only be a temporary observation.
High winds, blowing dust and low humidity can damage the leaves and stems on tomato plants. Heat and low moisture can cause the edges of the tomato leaves to die back, then twist and curl. Hot dry weather may also cause a symptom called physiological leaf roll.
When starting seeds, the temperature indoors should be 70-80 degrees. The growing mix should be moist, but not wet, to aid germination. Seeds don't need light to germinate, although after germination, you should ideally give the seedlings 14 or more hours of light a day.
Tomato plants, once they are established and growing leaves will thrive best with around a 12-15 hours per day of light.
Should you leave outdoor lights on at night? No, leaving lights on can make intruders think that you're not home. Use a motion sensor light that turns on when you, or anyone else, comes near so you have light only when you need it.