Summer fertilizer restrictions: what to do before and after they lift

Every summer we get the same question at the counter: can I fertilize my lawn right now? In much of Palm Beach County the answer from June until the end of the rainy season is no, at least not with nitrogen or phosphorus. As those restrictions start to lift, it is a good time to understand what they cover and how to plan your fall feeding.

The short version: check your own city's rules, wait for the restricted season to end, then feed with a slow-release product at the label rate.

Why the rules exist

Summer storms wash whatever is on the ground into storm drains, canals and the Lake Worth Lagoon. Nitrogen and phosphorus from lawn fertilizer feed algae blooms in those waters. Florida's fertilizer ordinances aim to keep those nutrients out of the water during the months when heavy rain makes runoff most likely.

North Palm Beach, for example, adopted its ordinance after the state found that some Palm Beach County water bodies were impaired in part by excess nutrients. Many other cities in the county have similar rules.

What is restricted, and when

The details vary from city to city, so look up your own. In general, the rules prohibit applying fertilizer that contains nitrogen or phosphorus to lawns and landscape plants during a summer restricted season. Many cities set that season from June 1 through September 30. Some run longer: North Palm Beach's restricted season runs June 1 through October 31.

Most ordinances also ban fertilizing on saturated soil, during a tropical storm or hurricane watch or warning, or when heavy rain is forecast. Many require a setback from water. North Palm Beach, for instance, requires 10 feet from ponds, canals, lakes and seawalls, or 3 feet with a deflector shield or drop spreader.

What you can do during the restricted season

The restrictions target nitrogen and phosphorus. Products without them, such as iron or micronutrient supplements, are generally allowed and can keep a lawn green through the summer. Read the label: the three numbers on a fertilizer bag are nitrogen, phosphorus and potassium, and you want the first two to be zero.

Summer is also a good time for the work that matters more than fertilizer. Mow at the right height for your grass type, since cutting too short stresses the lawn. Water only when the grass shows signs of thirst, like a blue-gray color or footprints that stay pressed in. Our post on how often to water your lawn has more.

Feeding once the restrictions lift

When your city's restricted season ends, fall is a good time for a feeding. Choose a fertilizer with slow-release nitrogen, which feeds the lawn gradually instead of all at once. Florida soils generally do not need added phosphorus unless a soil test shows a shortage, so a product with zero or low phosphorus is the usual choice.

Apply at the rate on the label and no more. Extra fertilizer does not make a greener lawn. It runs off, and it can encourage pests and disease. Sweep any granules off driveways, sidewalks and the street back onto the grass.

Test before you guess

If your lawn has struggled, a soil test tells you what it is actually short of instead of guessing. UF/IFAS Extension offers soil testing in Palm Beach County. A test for pH and nutrients costs little and can save you a season of fertilizing the wrong thing.

Sometimes the problem is not fertilizer at all. Bare spots, thinning grass and yellow patches often come from shade, poor drainage, pests or the wrong grass for the spot. Our guides to common lawn problems and bare spots can help you narrow it down.

Fertilizing shrubs, trees and palms

The ordinances usually cover landscape plants as well as turf, so the same timing applies to shrubs, hedges, trees and palms. Once your restricted season ends, a slow-release fertilizer suited to the plant type is the usual choice. Palms in particular need potassium, magnesium and manganese, and a dedicated palm fertilizer supplies them. Our post on fertilizing palms correctly covers the details.

Established trees and many native shrubs need little or no fertilizer once they are settled. If a plant is growing well and its leaves look healthy, it may not need feeding at all. Fertilizer is for a demonstrated need, not a calendar habit.

Hire a certified applicator if someone else does the work

If a lawn service fertilizes your yard, ask whether its applicators hold the Florida Green Industries Best Management Practices certification. Florida requires commercial fertilizer applicators to be trained and licensed, and certified crews know the local restricted season and setback rules.

It is also worth asking what they apply and when. A service that fertilizes on a fixed monthly schedule regardless of the season may be applying more than your yard needs, and it may run afoul of your city's rules.

Consider less lawn

Every square foot of lawn needs mowing, water and fertilizer. If part of your yard never thrives as grass, it may do better as a planted bed or a groundcover. Perennial peanut, sunshine mimosa and other Florida-friendly groundcovers need far less feeding and stay green with less water.

Bring a photo of the problem area to the nursery and we can suggest what will grow there. Our post on groundcovers that replace grass is a good place to start.

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