When To Fertilize Mums

Knowing when to fertilize mums is the key to a spectacular autumn display. Getting the timing right ensures your plants are strong, healthy, and covered in vibrant fall blooms.

This guide will walk you through the simple schedule. We’ll cover what to use and what to avoid. Let’s get your mums ready for their best season yet.

Fertilizing mums isn’t a year-round task. It has a specific season that aligns with their growth cycle. The goal is to feed them when they are actively growing and building the foundations for those flowers.

You should focus your feeding from early spring through mid-summer. Stop fertilizing after about July 15th. This deadline is crucial.

Late feeding encourages new, tender growth that won’t survive frost. It can also delay or reduce flowering as the plant puts energy into leaves, not buds.

The Essential Fertilizing Timeline

Follow this simple timeline for success. It works for both garden (hardy) mums and potted varieties you plan to keep.

Early Spring (As New Growth Emerges): This is your starting gun. When you see about 2-3 inches of new shoots, apply your first feeding.
Late Spring to Early Summer (Every 4-6 Weeks): Continue with regular feedings. This supports the rapid growth of stems and leaves.
Mid-Summer (July 4th – July 15th): This is your final application. Mark it on your calendar. Do not fertilize after this point.
Late Summer & Fall: No fertilizer. Let the plant harden off and focus entirely on bud development and blooming.

Why This Timing Works

Mums are photoperiodic. This means they sense the shortening days of late summer and begin to form buds. Fertilizing too late disrupts this natural signal.

The plant gets confused and keeps growing vegetatively. You end up with a large, green bush with few flowers. Sticking to the schedule ensures the plant’s energy is directed correctly at every stage.

Choosing the Right Fertilizer

Not all plant food is created equal. The numbers on the bag (N-P-K) tell you the ratio of Nitrogen (N), Phosphorus (P), and Potassium (K).

For Early Season Growth: Use a balanced, all-purpose fertilizer. A ratio like 5-10-5 or 10-10-10 is perfect. The nitrogen promotes healthy green growth.
For Bud Formation: As you approach your last feedings, you can switch to a fertilizer with more phosphorus. A formula like 5-10-10 encourages stronger roots and better blooming.
A Great Organic Option: Well-composted manure or a balanced organic granular fertilizer works wonderfully. It feeds the soil slowly and steadily.

How to Apply Fertilizer Correctly

Method matters as much as timing. Here’s how to do it:

Water the plant thoroughly a day before feeding. This prevents root burn.
Measure the fertilizer according to package directions for your plant size. More is not better.
For granular types, sprinkle it evenly around the base of the plant, starting a few inches from the stem and going out to the drip line (where the leaves end).
Gently scratch it into the top inch of soil with a hand fork.
Water deeply again to help dissolve the granules and carry nutrients to the roots.

Special Case: Potted Mums from the Store

Those gorgeous, bloom-covered mums sold in fall are already in their final stage. They do not need fertilizer.

They have been precisely fed in the nursery to bloom at that exact moment. Adding fertilizer now can harm the display. Just keep them watered and enjoy the show.

If you plan to keep them for next year, after the blooms fade, cut them back, plant them in the garden, and follow the spring feeding schedule.

Common Mistakes to Avoid

Even with good intentions, it’s easy to make a error. Steer clear of these pitfalls.

Fertilizing in Fall: This is the most common mistake. It stimulates new growth that winter will kill.
Using High-Nitrogen Lawn Fertilizer: This makes for weak, leggy growth and few flowers. Lawn food is for grass, not flowers.
Over-fertilizing: Excess salts from to much fertilizer can damage roots and actually prevent nutrient uptake. Follow the label.
Ignoring Soil Health: Fertilizer isn’t a substitute for good soil. Every few years, add compost to improve soil structure and microbial life.

The Importance of Watering with Feeding

Fertilizer and water are a team. Nutrients need moisture to dissolve and move into the roots. A dry, fertilized plant is under stress.

Consistent moisture is especially important during the spring and summer growth period. Aim for about 1 inch of water per week, from rainfall or your hose.

Preparing Mums for Winter

Your fertilizing schedule directly impacts winter hardiness. A plant fed properly and stopped on time is tougher.

After the first hard frost, cut stems back to about 2 inches above the ground. A light layer of mulch (like straw or shredded leaves) applied after the ground freezes can help protect the roots from freeze-thaw cycles.

This is especially helpful in colder climates. Avoid heavy, wet mulch that can smother the crown.

FAQ: Your Mum Fertilizing Questions Answered

Can I use Miracle-Gro on mums?

Yes, a water-soluble fertilizer like Miracle-Gro can be used. Use the all-purpose formula during the early growth phase. Apply it every 2-3 weeks as directed, but remember to stop by mid-July.

Is Epsom salt good for chrysanthemums?

Epsom salt provides magnesium and sulfur. Only use it if a soil test shows a deficiency. Yellowing between leaf veins can be a sign. If needed, a light side dressing in spring is sufficient. Don’t overuse it.

How do I get more blooms on my mums?

The recipe is simple: spring feeding for strength, timely pinching until early July to encourage branching, and no fertilizer after mid-summer. More branches means more bloom sites. Also, ensure they get full sun for at least 6 hours a day.

Should you feed mums in the fall?

No, you should not fertilize mums in the fall. Their growth cycle is complete. Feeding now can actually damage the plant’s natural hardening-off process and reduce its chance of surviving the winter.

What is the best natural fertilizer for mums?

Compost is the best all-around natural choice. You can also use well-rotted manure, alfalfa meal, or a balanced organic granular fertilizer from the garden center. These feed the soil ecosystem as well as the plant.

Getting your mums to produce vibrant fall blooms is deeply satisfying. It all hinges on understanding their simple needs. By feeding them consistently in spring and early summer, then stopping on time, you give them exactly what they need.

They will reward you with a breathtaking display of color just when the rest of the garden is starting to fade. Grab your calendar, mark the mid-July deadline, and look forward to your best mum season ever.