If I fertilize the lawn around my trees and shrubs regularly, do I have to apply extra fertilizer for my trees and shrubs, too? Probably not, a good lawn fertilization program will usually provide enough nutrients for landscape plantings in the lawn as well. Monitor the vigor and color of the landscape plantings and apply extra nutrients only if needed.
Should I water before or after fertilizing? Do not water before fertilizing, as the water on the grass will tend to make the fertilizer stick to the grass blades and burn them. Spread the fertilizer and then irrigate. The water will wash the fertilizer off the grass and into the soil, where the roots can use it.
Certain plants are not doing well even though I fertilize regularly - what is wrong? Some plants require acid soil, some need alkaline soil - for example, rhododendrons and azaleas require acidic soil to thrive. Or plants might have a specific micronutrient deficiency, or the nutrient balance could be off. For accurate results, do a soil test requesting analysis for micronutrients.
I use mulch, compost, and lime on my garden - is there any need to fertilize, too? Yes - your soil needs a good source of NPK - organic and synthetic. Mulch, compost, and lime enhance the plants' ability to use these nutrients, but do not supply them.
Should I keep kids and pets off the fertilized area? Probably not - after they are well watered, nutrient fertilizer granules in soil or mulch should pose no problem. The amount a child or pet could consume from the landscape is not enough to hurt them. If you use larger pellets or fertilizer stakes, be sure they are buried so children and pets won't try to eat them. Some fertilizer salts couldburn or cause skin irritations. If your fertilizer is a blend that includes pesticides, it is toxic - follow label instructions carefully.
Can I use pesticides in conjunction with fertilizer? Some pesticide/fertilizer combinations are premixed; for example, turf preemergent herbicide/fertilizer products. They are not premixed for ornamentals due to differences in species requirements and tolerances. Also, there is more even distribution of both if applied separately as they can be hard to keep evenly mixed unless in liquid form. Don't apply liquid fertilitzer and liquid herbicide with the same sprayer, unless your fertilitzer instructions specifically recommend mixing.
Can fertilizer be harmful to the environment? If improperly applied, especially in high concentrations, it can kill earthworms. If you apply too much N, it can stimulate too much vegetative growth at the expense of flower/fruit formation. Over fertilized lush plants are more susceptible to pests and drought. Applying too much fertilizer or at the wrong time can increase leaching into groundwater. Fertilizer increases the rate of decomposition of organic material, so it's important to add more organic matter periodically.
When should I apply fertilizer? Timing is more critical if you use a fast release fertilizer - either early spring or late fall application is most effective, when roots are growing but top is slow or dormant. Avoid late summer fast release fertilitzer application, as it may cause a flush of tender growth that will be damaged by frost. A slow release fertilizer may be applied anytime during the growing season.?