Trees and shrubs that need fertilization to stimulate more robust and vigorous growth include those exhibiting pale green, undersized leaves and reduced growth rates and those in declining condition (for example, dead branch tips, called dieback) resulting from insect attacks or disease problems.
Older oak trees generally need fertilization about once a year. Maple trees usually tell you if they need to be fertilized. The rule of thumb is that if they grow about 6 inches in a year, the soil is good, but if the growth is less than 2 inches, it's time to fertilize.
The best method for assessing nutrient availability in your garden is to do a soil test. A basic soil test from the University of Minnesota's Soil Testing Laboratory will give a soil texture estimate, organic matter content (used to estimate nitrogen availability), phosphorus, potassium, pH and lime requirement.
A: DO NOT SPRINKLE the granules directly onto the soil!!!. It will burn and kill your surface roots. Use as directed or buy a sprinkle alternative.
When applying fertilizer, always read and follow all label directions carefully - too much fertilization can permanently damage trees and plants. Excess fertilizer alters the soil by creating too high of a salt concentration, and this can hurt beneficial soil microorganisms.
Fertilizers can quickly save your trees from dying. However, not applying them properly will damage your trees more. You should also know the right types of fertilizers to apply. Organic fertilizers are better than artificial ones.
If you have a variety of trees and shrubs in your garden, you can use an all-purpose plant food like Miracle-Gro® Shake n Feed® Flowering Trees & Shrubs Continuous Release Plant Food which will feed for up to 3 months.
If you're not supposed to fertilize during heavy rains, you're also not supposed to fertilize on scorching days. During these days, lawns tend to lose their ability to retain moisture. When this happens, your lawn becomes drier and less able to absorb nutrients.
You should water granular fertilizer immediately after it is applied to your plants. Granular fertilizer needs the help of water for it to activate, so it will have no effect on your garden if you forget to water after adding it. For liquid fertilizer, you should wait longer before watering your plants.
Nutrient deficiency symptoms occur as yellowing of leaves, interveinal yellowing of leaves, shortened internodes, or abnormal coloration such as red, purple, or bronze leaves. These symptoms appear on different plant parts as a result of nutrient mobility in the plant.
It depends on the fertilizer. Some lawn foods perform better when you water them in right after applying, while others—such as some weed-and-feed products—need to be watered a day or two after fertilizing. It all comes down to this: Check the product directions on the bag—they'll tell you when to water.
In general, with good plant health care, it takes around four to six weeks for fertilizer to work on trees. That is because it takes a while for the fertilizer to be absorbed by the tree's roots and for the nutrients to spread throughout the rest of the tree.
Treating a Sick Tree
If your tree shows signs of illness, you want to avoid putting fertilizer near the root zone and using pesticides. Additionally, you should avoid over-mulching and overwatering. Proper pruning practices should also be done, and exposed roots should be hand trimmed.
Timing: Apply fall lawn fertilizer once between August and November, right before winter hits, six to eight weeks after the summer feeding.
For all trees and shrubs.
If needed, the best time to fertilize is late April or early May, or late fall once plants are dormant. The recommended fertilizer should be spread evenly across the soil surface.
In order to prevent chemical interaction and corresponding precipitation between fertilizers, it's important to use the right combination of fertilizers. Neither phosphoric nor sulphatic fertilizers should be mixed with calcium or magnesium containing fertilizers in the same tank.
Slow-release nitrogen fertilizers are best for woody plants, with one-third to one-half of the nitrogen in a water-insoluble, slowly available or slow-release form. Shrubs and trees absorb fertilizer during their active growth period: from spring, when growth begins, to late summer and early fall.
Miracle-Gro actually stresses your plants out and makes them more susceptible to pests and disease. Miracle-Gro contributes to air pollution. Miracle-Gro can actually make your plants less productive and less healthy. Miracle-Gro is harmful to human health.
Peeling or loose bark or cracks in the tree around the tree's root collar. Swelling, soft or decaying wood, or small holes in the tree trunk. Dead, dying, or drooping branches in the canopy. Wilting, discolored, or damaged leaves.
A deep, slow, soaking watering just after you fertilize will insure that the nutrients get to the roots. Doing it just before a good rain is even better. Whatever you use should be applied once or twice a year.