BALANCING GROWTH IN THE GARDEN
Young plants are often highly vegetative in the early stages of growth.
Flowering Triggers and Forcing
For many plant species, flower formation happens
when the plant is mature enough and growing
conditions are right for this to occur. However,
there are exceptions. Some commonly grown
species have day-length requirements
(photoperiodism) or require a period
of exposure to cold (vernalization)
before they will initiate flower buds.
For example, spinach requires a long photoperiod (day
length) to initiate flowers, but rice requires a short day
length. Day-neutral plants such as cucumbers and tomatoes
do not initiate flowers based on day length, but flower once
they reach a certain size or age, or in response to other
environmental conditions such as temperature. Strawberries
can be either short-day, long-day or day-neutral.
To confuse matters further, some plants need certain
In overly warm climates, chilling the nutrient
solution is an effective way of delaying the
flowering phase.”
combinations of day length, temperature, plant maturity
and environmental conditions for flowering. Furthermore,
the number of flowers and strength of blooms, pollination
and fruit set are also influenced by a wide range of different
factors both within the plant and the growing environment.
Flowering cannot be initiated by simply switching to a
bloom nutrient formation. Bloom nutrients are specifically
designed to provide the different ratio of elements required
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Maximum Yield USA | October 2015
for flower and fruit tissue development, not to force
a plant into flowering when it is not physiologically
ready to do so.
Unwanted Flowering
Crops grown for their vegetative parts, such as
lettuce and herbs, can flower prematurely.
Typically this occurs most rapidly under
high light, long days and warm conditions,
especially with cool-season crops like lettuce, spinach,
endives and radishes. Basil is also prone to early flowering
in hot summer growing conditions, limiting the amount
of leaves that can be harvested. In overly warm climates,
chilling the nutrient solution is an effective way of delaying
the flowering phase, allowing the plants to grow enough
foliage for harvest. Other methods include shading plants to
reduce temperatures, growing slow-bolt cultivars, avoiding
overcrowding and cooling the growing area.
Fruit Upsizing
Small, undersized flowers and fruits are a common
complaint, particularly amongst tomato growers. Sizing up
slow-growing fruits is based on the fact that the warm parts of
the plant (buds, leaves and fruits) attract more sugars than
cooler parts. A small difference in temperature can make a
considerable difference in the distribution of sugars within
plants, and warm fruits attract more sugars for growth.
The optimal fruit tissue temperature for importing sugars
and upsizing a tomato fruit is around 73-77 oF. Growers use
a technique called a pre-night drop to help boost fruit size.
This process involves increasing the heat in the late afternoon, which is absorbed by the fruit tissue, while sugars