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Fall Fertilization

Right now is a great time to fertilize!

By Chris Leinster - August 21, 2018

Right now is a great time to fertilize your lawn and garden plants. As summer heat wanes Bluegrass and other turf species start sending nutrients to the roots and storing energy for winter dormancy. Apply one pound of nitrogen per one thousand square feet two to three times during the fall season to supply your lawn with necessary nutrients during this critical growth period. Fall fertilization encourages roots to penetrate deeply into the soil resulting in healthier and more drought tolerant turf.

This advice may sound counterintuitive if you’ve been conditioned to fertilize in the spring. Spring fertilization can promote excessive top growth leading to a stressed and burned out lawn when summer’s scorching heat arrives. While Iron and micronutrient fertilizers are beneficial in the springtime, nitrogen-based fertilizers are best applied in the fall.  You can review our advice for spring lawn fertilization here:

All fertilizers carry an analysis which indicates the percentages of the three primary plant nutrients, which are nitrogen, phosphate, and potash, and displayed as 20-10-10 (or any combination of numbers relating to how this particular brand of fertilizer was formulated).  In this example the bag contains 20% nitrogen, 10% phosphate, and 10% potash. Along the Front Range, our soil generally contains sufficient phosphate and potash, so select a formulation with less than 10% of these nutrients.

Nitrogen is major building block of plant cells and is primarily responsible for stimulating growth. Applying nitrogen in the fall stimulates desirable root growth rather than excessive top growth. The Colorado State University Extension Service recommends that one pound of nitrogen per thousand square feet should be applied to lawns from mid-August to mid-September, and another one pound of nitrogen per thousand square feet should be applied from early October to early November. Therefore, you should look for a fertilizer with no more than 20% nitrogen for a fall application. The North Carolina Department of Agriculture has a simple guide to help you calculate how much fertilizer to apply in order to achieve one pound of nitrogen per thousand square feet of turf:

One of the most exciting advances in agricultural science is the introduction of live cultures of beneficial bacteria and fungi into our soil for the benefit of agricultural crops and landscape plants, including lawn grasses. We are only recently beginning to understand the essential role that beneficial bacteria and fungi contribute to promote a healthy soil ecosystem that supports plant life above ground.  These products are now becoming commercially available and I would encourage you to seek them out at your local garden center or nursery and incorporate them into your gardening practices.

With a good spreader fertilizing is perhaps one of the easiest chores that any homeowner can accomplish with the right information. Knowing what type of fertilizer to apply at the proper time of year can help you achieve a lush landscape sustainable for many generations to come. Check back often for other seasonal gardening tips. Thank you for your consideration of Happy Trees and have a great day!