Water, air, light, soil nutrients, and the correct temperature for the right plants are the most basic factors to make a plant grow faster and bigger.

Way and Oren (2010) found that increased temperature generally increases tree growth, except for tropical trees. They suggest that this probably occurs because temperate and boreal trees currently operate below their temperature optimum, while tropical trees are at theirs.

In the future, this could help breed plants that are adapted to global warming. Plants react much more sensitively to fluctuations in temperature than animals. “When temperatures rise, plants grow taller in order to cool themselves off. Their stalks become taller and their leaves become narrower and grow farther apart.

When temperatures spike above 85 degrees Fahrenheit, plants can lose a lot of the water that they need to grow. If this is condition is ignored, the plants will eventually dry up and turn crunchy brown or yellow before dying.

Plants function in a similar way to cold-blooded animals, in that their metabolism and the rate of photosynthesis increase in line with the ambient air temperature. When temperatures are very low (how low depends on the plant variety), hardly any photosynthesis will occur, regardless of how much light there is.

The original purpose of this experiment was to see in which soil temperature (32°c, 18°c or 5°c) more seeds will sprout. The results of the experiment showed that A and B sprouted faster then the other four by one day.

Some plant seeds, including cool season vegetables like lettuce and broccoli, germinate best in temperatures between 55 and 70 degrees F. (13-21 C.), while warm season plants such as squash and marigolds, germinate best when temperatures are between 70 and 85 degrees F.

High temperatures speed up the normal living process of plants to a maximum rate at and above 90 degrees F. This means that most plants can take temperatures up to 90 degrees F. fairly well. Anything above that—the hotter it gets, the more they suffer!

The general answer is around 90 degrees F, with some exceptions to the rule. This means that when temps rise above 90 and remain there for a lengthy spell: Leaves wilt. Water evaporates into the atmosphere more quickly in high heat, draining a plant’s reserves.

Generally, heat stress of a plant will show itself by wilting, which is a sure sign that water loss has taken place. If this is ignored, the condition will worsen, as the plants will eventually dry up, turning a crunchy brown before dying. In some cases, yellowing of the leaves may occur.

The books are right – planting in the summer when it is hot and dry is not the best time to move new plants into or around the garden. During a particularly bad heat wave it can be hard enough to keep the soil hydrated, let alone provide ample moisture for plants that are establishing new roots.

Roses thrive in full sun. When they get anywhere from 6 to 8 hours of sun a day, they bloom vibrantly and to their fullest. Any variety will be spectacular when grown in these conditions. They are hardy in zones 4-9 and with the right care, can come back to thrive year after year.

Revive the plants quickly by setting their pots in a sink filled with room-temperature water. The water should come about halfway up each pot’s side. Leave the pots in the sink for at least one hour, or until the soil feels wet at the top to you; for some plants, the process can take several hours.

So to that end, the best thing I can advise you to do is move it into a cool, shady spot. Plants in the sun use more water. Give it some water. Keep it consistently moist (not wet) and do not let it dry out between watering.

Cut back any brown leaves or flowers and scale back the use of fertilizer. Water the hydrangea well to try to dilute the water soluble nitrogen in the soil to help the hydrangea revive.

When hydrangeas are drooping, they’re often expressing their dislike of local conditions. Too much sun and not enough water lead to wilt; heavy flower loads can cause tender branches to bend until they touch the ground.