4 Reasons to Not Over-Fertilize Your Lawn

Updated on August 12, 2017
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Catherine is a California-certified nursery professional. Her interests are birds, insects, integrated pest management, & organic gardening.

Big box garden centers push the use of high nitrogen fertilizers by stacking palettes high and offering sale prices.
Big box garden centers push the use of high nitrogen fertilizers by stacking palettes high and offering sale prices.

Instant gratification may be the way of the world today, but nature runs by a different clock. Gardening teaches patience and forces us to slow down and follow the seasonal cycles of rest and growth. Reducing fertilizer use is a good first step.

4 Reasons to Avoid Excess Fertilizer Applications:

  1. The accumulation of salts will weaken both plant health and soil structure.
  2. Too much fertilizer will promote new growth flushes and increase insect damage.
  3. Rapid growth means an increased need for water. This is impractical with critical drought situations throughout the world.
  4. The run-off of phosphorus promotes algae bloom in our streams and ocean. It is a serious neurotoxin to dolphins, otters, sea lions, and whales.

The algae bloom from fertilizer run-off is deadly to sea mammals.
The algae bloom from fertilizer run-off is deadly to sea mammals.

Domoic acid toxicity in seafood and shellfish is becoming a bigger threat to sea mammals and humans alike. Algae bloom from high levels of phosphorus pollution is prevalent in many coastal areas like Southern California where sightings of dead or beached sea lions is becoming all too common.

Be Willing to Let Go of Instant Gratification

I can certainly appreciate a person's desire for magnificent, non-stop blooms and lushness which can be had with weekly feedings from a sprayer. These fertilizers force plants to maintain top performance which depletes vigor for successive seasons; therefore, these water-soluble fertilizers work best with showier annuals in containers. On lawns and in garden beds, a slower, organic approach works best for a number of reasons.

First, we are not only feeding our plants, we are also sustaining the microbial life which supports healthy roots and promotes efficient nutrient uptake. Composting is a recycling process in itself, and it provides food for beneficial decomposers and aerators like pill bugs, ants, and earthworms which break down the carbons in organic matter and render them more readily available to plants. These hard working organisms increase the amount of humus in the soil and leave behind mineral-rich excreta (worm castings.) Monthly top dressings of well composted organic materials add structure to the soil, reduce the need for both water and nitrogen fertilizer, and help control weed growth. Organic fertilizers and compost also contain fewer salts which are toxic to plants in high amounts. Excess sodium weakens tissue growth, makes plants more susceptible to insects and disease, and can damage soil structure over the long term. Instead of spraying a commercial fertilizer each week, consider the option of a homemade compost tea.

How to Apply Fertilizer Correctly

When it comes to fertilizers, both organic and chemical varieties provide the same 17 essential building blocks for plant growth. The 3 primary ones—nitrogen, phosphorus, and potassium—always appear on product labels, showing as 5-3-1 or 15-15-15 for example. The first, nitrogen, promotes good foliar or green growth; the second, phosphorus, encourages flower and fruit production; and the third, potassium, insures overall health, strong roots, and good cellular structure. Of course, be aware of the natural growth cycles of your plants and fertilize accordingly. Do not feed when plants are dormant. Fertilizers should be used when plants are actively growing.

Lawns: Consider the type of turf grass in your yard. Cool season grasses like rye, fescue, and bentgrass tend to slow their growth in the heat of summer. These lawns do best when fertilized during the fall when growth is most active. Warm season grasses like Bermuda, Zoysia, and St. Augustine go dormant and turn brown when temperatures dip. These grasses should be fertilized in the spring when the lawn has fully greened up with the increasing temperatures. The last application should be 6-8 weeks before the first frost. There are lawn specific fertilizers which are primarily nitrogen based, and there are other products which can be cast all over the garden to feed lawns, trees,and shrubs. It is important to thoroughly read labels of each for proper application so as to not burn the grass.

If a non-organic fertilizer is the norm for your lawn, cut the application amount in half and spread the feedings 2-3 months apart. Typically, lawn services will feature programs which feed lawns 4 times per year with each season. Spring applications include herbicides for pre-emergent weed and crabgrass control, and summer ones add extra nitrogen for green-up and pesticide to kill turf pests like grubs, cinchbugs, leatherjackets, armyworms, and sod webworms. Fall and winter feedings are higher in potash to encourage strong root structures. These programs result in nice looking lawns, but they make me wonder what poisons linger there when I walk barefoot. My pets like to eat the grass, and my kids play on it. What about those golfers who lick the golfballs for a clean putt? Yech!

More Natural Tips for a Healthy Lawn

  • Cut fertilizer amounts in half. Cutting back on feedings may be a hard habit to form but is well worth the effort. The transition should be gradual for best results.
  • Leave grass clippings as natural mulch. This will encourage earthworms and improve water penetration and healthy roots.
  • Keep mower blades sharp. Set mower blade height 2 1/2"- 3" in summer.
  • Avoid removing more than 1/3 of grass height at a time.
  • Water 20 mins. twice a week in hot seasons instead of five times for 5-10 minutes. Heat stressed spots needing extra water can be sprinkled by hand. If penetration is a problem, water until the point of run-off, turn off the sprinklers, let the water soak in, then cycle again 1 hour later.
  • Adjust timers to meet seasonal needs.

Leonardite Is A Great Organic Lawn Fertilizer

Leonardite, an oxidized by-product of lignite found in coal beds, is rich in humic acid and makes a great organic lawn fertilizer. It conditions the soil and improves water penetration to promote deep root growth. Applied twice yearly with compost dressing and combined with the healthy practice of productive, less frequent watering, this nutrient will keep the lawn vigorous and pest-resistant throughout the growing season.

Organically treated lawns bring peace of mind where family safety is concerned.
Organically treated lawns bring peace of mind where family safety is concerned.

Common Concerns

Dead spots are often fungal related and are made worse by over-water whereas wilted grass will take on a bluish tint and won't spring back when touched. Fungal issues can usually be reversed with watering corrections or can be evaluated by a nursery professional who will recommend the proper fungicide.

Lawn Insect control should really only be used when specific pests have been identified in large populations. Beneficial nematodes can be diluted and applied by sprayer to address grub, chinch bug, and other turf pests. These biological controls can be ordered from www.tiptopbio.com. Another good source for integrated pest management is the UC IPM website.

Going organic may seem slow at first, like putting coins in a jar. If you keep at it, however, you will eventually see a big payload: a lush lawn with healthy roots and a garden with fewer weeds. There is also the confidence that comes from knowing that your beautiful green areas are not harming your health nor that of your children, pets and wildlife.

Questions & Answers

    © 2011 Catherine Tally


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      • FlourishAnyway profile image

        FlourishAnyway 3 years ago from USA

        I'm so glad you provided an alternative. This is a very timely hub this time of year. Anything we can to to help give back to Mother Nature.

      • cat on a soapbox profile image

        Catherine Tally 3 years ago from Los Angeles

        Hello Ted. Thank you for sharing the blog. I think the reasoning makes sense, and timing IS everything. Yes, fertilizer is to be applied when growth is active and does best before the stress of heat. Healthy roots will crowd out weeds too. Here in drought-stressed So. California it is imperative to irrigate deeply and less often w/ our water restrictions. Fertilizer stimulates new growth which requires more water, so it should be done sparingly. Keeping blades longer and leaving mowed clippings on the lawn helps the turf stay cooler and the soil moist longer. Thank you for stopping by to read. I appreciate the thoughtful comments.


      • profile image

        Ted Tanka 3 years ago

        Great Hub. Thank you.

        I found another blog on a blog I like to read for lawn tips where the author talks about how to remember when to fertilize. I like how he links it to holidays as a really easy way to remember.

        Let me see if I can find the blog.... here goes....


      • cat on a soapbox profile image

        Catherine Tally 7 years ago from Los Angeles

        Thank you,dobo700. I'm glad you found it helpful. Hope you drop by again :>)

      • dobo700 profile image

        dobo700 7 years ago from Australia

        Nice Hub - excellent tips and advice.

      • cat on a soapbox profile image

        Catherine Tally 7 years ago from Los Angeles

        Thank you, Harlan. That's quite a compliment! Thanks for following.

      • Harlan Colt profile image

        Harlan Colt 7 years ago from the Rocky Mountains

        This is a great hub. I am going to book mark it. This is also the first hub I have bookmarked. Welcome to hub-pages Soapbox Cat. I look forward to more of great hubs. I am voting up!

        - Harlan