One of the important reasons to foliar spray is to guide or direct plant physiology. Before doing this with foliar sprays you must understand the plant you are growing.
Plants have two basic modes or states they can be in. Either they are growing vegetatively or they are growing reproductively. In the vegetative mode plants vigorously produce stalks, stems, and leaves. Growth or vegetative energy also helps plants bulk up or increase in size. Reproductive energy results in the formation of blossoms, flowers, and pod set.
Let's look at the life cycle of a few crops to see these two modes in action.
Cabbage: The crop starts out vegetative; it remains the same way as it puts out more and more leaves. As the leaves are wrapped up into a head it is still in a vegetative state. If unharvested or exposed to plenty of heat as the head forms or if the plant is in a highly reproductive environment the head will split and the plant sends out a reproductive seed head.
In Summary: Growth - Growth - Growth - Harvest
Corn: Corn starts out vegetative; it remains in this state all the way till pre tassel when it switches over to a reproductive mode ahead of pollination. When pollination is complete the corn must fill the kernels so it is back to vegetative mode but without new leaves. Once pollination is complete the only way to increase yield in corn is to fill the kernels and make them as heavy as possible. You can't make new kernels.
In Summary: Growth - Reproductive - Growth/Bulking - Harvest
Soybeans: Soybeans start out as vegetative; this continues up to the time of summer solstice. Once the hours of sunlight begin to shorten, this switches the plant to a reproductive mode that initiates pod set. From this point on, soybeans put out new pods until they shut down just before harvest.
In Summary: Growth - Reproductive - Reproductive - Harvest
Apples: Apples start the season with early blossoms hence it begins reproductively. After petal drop the tree switches to growth energy as it finishes leafing out and begins to bulk the new apples. Immediately after harvest it switches back to reproductive energy as it prepares internally for next year's blooms.
In Summary: Reproductive - Growth/Bulking - Harvest - Reproductive
Asparagus: Starts out with early vegetative growth which is immediately harvested. After the harvest season the plant puts out more vegetative growth and then ends the season reproductively as it blooms and sets seeds. During the mid and late season the asparagus plant builds up its reserves of minerals and carbohydrates in the root mass for next spring's early yield.
In Summary: Growth/Harvest - Growth - Reproductive
As we look at each of these crops there are many lessons and implications as it relates to foliar feeding. Here are just a few.
1. Crops like cabbage including cauliflower, broccoli, spinach, and kale should never be sprayed with a strongly reproductive foliar spray. The reason is because this will stop the vegetative growth by switching the plant to reproduction. The exception to this is if you are a seed producer for these crops. In that case begin reproductive foliar sprays at mid-season.
2. Temperature, environment, fertilization, and crop stage all play a significant role in determining which mode (growth or reproductive) plants are in.
3. A strong growth/bulking spray on corn and soybeans at the wrong time can cause a significant decline in yield. If corn is has poor pollination because of the foliar spray there is no way to get that yield back. Soybeans are more forgiving because you can stimulate pod set later on.
4. Be very careful not to apply the wrong kind of spray at the wrong time.
5. Perennial crops such a fruit and nut trees store nutrients and energy over the dormant season for next year's crop. This means you can use foliar sprays to enhance storage in the roots and wood tissue. A frequent foliar program on fruit and nut trees creates a cumulative benefit for next year's crop.
6. Certain crops such as corn have a very limited window for reproduction. After that they cannot return. Therefore it is okay to use some reproductive sprays during the filling stage to supply specific trace minerals needed by the plant.
7. The key to effective foliar sprays is to tell the plant to do what it already wants to do.
Foliar sprays can be amazingly powerful when used to push plants toward vegetative growth or toward reproduction. Think of the balance on a teeter totter. A slight increase of weight on one side can shift the balance from one side to another. Foliar sprays can do the same thing with crop physiology.
Here are a few foliar sprays to push plants into reproduction and greater yield using the formulas below. Foliar Spray Soybeans at least 2 times. Here are a couple examples:
Foliar Spray per Acre:
2 quarts Bloomit
4 oz. Boric Acid
2 lbs. Dextrose
Water As Needed
Cost Per Acre = $10.28
After 2 Weeks Foliar Spray per Acre:
1 quart Bloomit
1 quart WayAhead 7X
2 lbs. Dextrose
Water As Needed
Cost Per Acre = $11.40
For gardens try:
1 quart Distilled Water
2 tablespoons Dextrose
25 mills Bloomit
15 mills RL-37
Apply with a light misting. Do not use on leafy greens, cabbage, cauliflower, vegetative herbs, or wheat grass. To make your own reproductive foliar spray you may wish to use a recipe like this:
1 quart Distilled Water
2 tablespoons Dextrose
25 mills Phosphoric Acid stabilized Liquid Fish
10 mills Plain Household Ammonia
5 mills Fulvic Acid
In an upcoming article we will look at how various nutrients provide growth or reproductive energy.
