Frequently Asked Questions - Soils, Fertilizing, and Composting

Winter mulches are applied to plants, such as strawberries and chrysanthemums, in fall to prevent damage caused by extreme cold or repeated freezing and thawing of the soil during the winter months. Leaves are a poor winter mulch for strawberries…

Leaves are not a good winter mulch for strawberries.  Leaves can mat together in layers, trapping air and creating space for ice to form.  The leaf, air, and ice layers do not provide adequate protection.  A leaf mulch may actually…

Keep Leaves in Place, When Possible

Leaving the leaves alone is a good way to support native pollinators and other insects and wildlife.  These valuable insects rely on the habitat fallen leaves provide, especially over the winter…

Black walnut (Juglans nigra) is a common woodland and landscape tree in the Midwest. 

Much has been written about the allelopathic properties of black walnut.  When plants produce a chemical that prevents the growth of…

Yes. While oak leaves are slightly acidic, an oak leaf mulch should have little effect on the soil pH. Shredded leaves are an excellent mulch for vegetable gardens, raspberry plantings, perennial flower beds and around trees and shrubs. Oak…

Knowing the area of the garden bed or lawn is necessary for applying fertilizers or pesticides, determining how much mulch is needed, or determining the number of plants needed to fill a space.

The method for determining the area of your…

If fallen leaves are collected, there are a several options for what you can do with them. 

Add Leaves to the Compost Pile

Whenever possible, keep this valuable organic resource on-site.  Leaves can be added to a compost…

Soil testing services are provided by neighboring universities and private laboratories.  Information on how to collect good soil samples for testing and recommendations for how to find testing laboratories can be found at …

In Iowa, Kentucky bluegrass lawns can be fertilized in spring (April or May), mid-September, and late October/early November.  The number of fertilizer applications is largely determined by an individual’s desires or expectations for their…

Fertilization is generally not necessary during the winter months as most houseplants are not growing during this time.  Indoor gardeners should fertilize their houseplants on a regular basis in spring and summer when plants are actively…

It is generally not necessary to fertilize healthy, vigorous trees and shrubs in the home landscape.  Most landscape soils in Iowa contain adequate levels of nutrients for trees and shrubs.  Plus, trees and shrubs that are growing in…

Leaves are an excellent resource for the garden. They break down to add organic matter and nutrients to the soil. As they decompose, they act as a mulch suppressing weeds and helping to maintain consistent soil moisture. Additionally, they can…

The nutrient content of composted leaves is very small. The levels of nutrients vary somewhat from species to species. However, the nitrogen content of composted leaves on a dry basis usually varies from 0.5 to 1.0 percent. Potash amounts are in…

Most lawns in Iowa are comprised of Kentucky bluegrass and other cool-season grasses.  Cool-season grasses grow best in spring and late summer/early fall when environmental conditions are usually favorable.  Applications of fertilizer…

Fertilizer applications can be made in mid-September and late October/early November.  Mid-September fertilization promotes a moderate rate of shoot growth and helps to thicken the turf.  An application of fertilizer in late October/…