September 1, 2025

Fall Care Tips: Knowing When to Stop Feeding Perennials

Fertilizing is an important part of keeping perennials healthy, colorful, and strong. But as the growing season winds down, knowing when to stop fertilizing is just as important as knowing when to start. Giving plants the right nutrients at the right time sets them up for success year after year.

Why Fertilizer Timing Matters

Perennials go through seasonal rhythms. In spring and summer, they focus on putting out fresh growth and blooms, so they need the extra boost that fertilizer provides. As fall arrives, perennials start shifting their energy underground, storing food in their roots to survive the winter and return strong in spring.

If you fertilize too late in the season, you risk encouraging tender new growth that won’t have time to harden off before winter. That fresh growth is more likely to be damaged by frost, which can weaken the plant overall.

The General Rule of Thumb

In New England and other northern climates, it’s best to stop fertilizing perennials by early September. This gives plants time to slow down naturally and prepare for dormancy. Further south, where the frost arrives later, you can usually extend that window into late September.

Signs It’s Time to Stop

Instead of focusing just on the calendar, pay attention to your plants:

• • Blooms are slowing down or finished.
  • Stems and leaves are starting to toughen up or fade.
  • Cooler nights are becoming the norm.

These cues are your perennials’ way of saying, “I’m ready to rest.”

 

What to Do Instead

Once you’ve stopped fertilizing, shift your focus to preparing your perennials for the months ahead:

• • Water deeply until the ground freezes, especially during dry fall weather, to help plants store up moisture.
  • Mulch around the base of perennials to insulate roots and regulate soil temperature.
  • Clean up spent foliage to help prevent disease and pests overwintering in the garden.

 

The Payoff in Spring

By stopping fertilizer at the right time, you allow your perennials to naturally wind down for the season. Come spring, they’ll reward you with healthier growth and stronger blooms—proof that a little patience in fall pays off in the long run.  Check out our blog on pollinator-friendly fertilizers, so you’ll be ahead of the curve when Spring rolls around!