When To Fertilize Daylilies

If you want your daylilies to produce a spectacular show of flowers, knowing when to fertilize daylilies is the most important step. Getting the timing right gives your plants the nutrients they need exactly when they need them, leading to healthier foliage and more blooms.

Daylilies are famously tough, but they do benefit from a thoughtful feeding schedule. This guide will walk you through the essential calendar for fertilizing, from early spring to late summer, so you can support your plants all season long.

Your fertilizing schedule should follow the natural growth cycle of the daylily. The goal is to feed the plant as it wakes up, as it prepares to bloom, and after it has finished its main display. This three-phase approach supports the entire plant.

1. Early Spring: The Wake-Up Feed

This is your first and most crucial application. Apply fertilizer as soon as you see new green shoots (fans) emerging from the ground in early spring. This gives the plant a major boost for developing strong roots and lush foliage, which sets the stage for flowering.

Timing: When shoots are 2-4 inches tall.
Goal: Support early leaf and root growth.
Tip: If you have a late frost after feeding, don’t worry. The nutrients are already in the soil ready for the plant.

2. Pre-Bloom: The Bud Booster

A second feeding just before the bloom stalks (scapes) start to form can encourage more and larger flowers. This is especially beneficial for heavy-blooming modern cultivars.

Timing: About 4-6 weeks after the spring feed, usually when scapes are visible but buds are not yet swollen.
Goal: Provide energy for bud formation and strong flower stalks.
Tip: Avoid high-nitrogen fertilizers here, as they promote leaves at the expense of flowers.

3. Post-Bloom: The Replenishment Feed

After the main flush of flowers fade, your daylilies are exhausted. They shift energy to root development and storing nutrients for next year. A final light feeding helps with this recovery.

Timing: Shortly after the last blooms fade, typically in mid to late summer.
Goal: Replenish the plant and support next year’s flower buds already forming inside.
Important: Do not fertilize too late in the fall. This can promote tender new growth that will be killed by frost.

What Type of Fertilizer Should You Use?

Choosing the right product is just as important as timing. A balanced, slow-release fertilizer is often the best and safest choice for daylilies.

Balanced Formulas: Look for an N-P-K ratio like 10-10-10 or 5-10-5. The middle number (Phosphorus) is key for good blooming.
Slow-Release Granules: These provide a steady supply of nutrients over many weeks, reducing the risk of burn and the need for constant reapplying.
Organic Options: Well-composted manure, compost, or fish emulsion are excellent. They improve soil structure as they feed.
Low-Nitrogen Bloom Foods: For the pre-bloom feed, a formula like 0-20-20 can be very effective.

How to Apply Fertilizer Correctly

Proper application ensures the roots can access the nutrients without harm to the plant.

Water the daylilies thoroughly a day before feeding if the soil is dry.
Scatter granular fertilizer evenly around the base of the plant, starting a few inches from the crown and extending out to the drip line (where the leaves end).
Gently scratch the granules into the top inch of soil with a hand cultivator.
Water deeply again after application to help move the nutrients into the root zone.
Avoid letting fertilizer touch the plant’s crown, as it can cause rot or burn.

Signs Your Daylilies Need Fertilizer

While following a schedule is best, your plants will tell you if they’re hungry. Watch for these clues:

Reduced Number of Blooms: Fewer flower scapes or smaller clusters than usual.
Pale or Yellowing Leaves: Especially in newer growth, which can indicate a nitrogen deficiency.
Stunted Growth: Fans that are smaller or less vigorous than in previous seasons.
Poor Scape Strength: Flower stalks that are thin or flop over easily.

Common Fertilizing Mistakes to Avoid

Even with good intentions, it’s easy to make errors. Here are the big ones to steer clear of.

Over-fertilizing: More is not better! Excess fertilizer, especially nitrogen, leads to lots of leaves and few flowers. It can also burn roots and pollute waterways.
Fertilizing Too Late: Feeding in early fall stimulates new growth that won’t harden off before winter, making the plant vunerable to cold damage.
Using the Wrong Formula: A lawn fertilizer (high nitrogen) will give you a beautiful green bush with no blooms.
Ignoring Soil Health: Fertilizer feeds the plant, but organic matter like compost feeds the soil. Healthy soil grows healthier daylilies with less need for chemical inputs.

Special Considerations for Newly Planted Daylilies

Your approach should be different for new plants. They need time to establish roots before being pushed with fertilizer.

At Planting: Mix compost into the planting hole, but hold off on chemical fertilizers.
First Spring: Wait until the plant is actively growing (about 4-6 weeks after spring emergence) for its first light feeding.
First Year Goal: Focus on root establishment. A strong root system in year one leads to a spectacular bloom in year two and beyond.

The Role of Soil Testing

For the most accurate fertilizing plan, nothing beats a soil test. It removes the guesswork.

A test will tell you your soil’s pH (daylilies prefer slightly acidic to neutral, 6.0-7.0) and exactly which nutrients are lacking or abundant. You can then choose a fertilizer that corrects specific deficiencies, which is more efficient and economical. Your local cooperative extension office usually offers low-cost testing.

FAQ: Your Daylily Fertilizing Questions Answered

Can I fertilize daylilies when they are blooming?
It’s best to avoid it. Fertilizing during peak bloom can actually shorten the bloom time and stress the plant. Stick to the pre-bloom and post-bloom schedule.

Is Epsom salt good for daylilies?
Epsom salt provides magnesium. Only use it if a soil test shows a deficiency. Unnecessary use can harm soil balance. It is not a substitute for a complete fertilizer.

How often should you feed daylilies?
For most gardeners, the three-times-per-season schedule (spring, pre-bloom, post-bloom) is perfect. In very poor soils, you might need an extra light feeding, but in rich soils, once in spring may be enough.

What is the best natural fertilizer for daylilies?
Well-aged compost or manure is ideal. You can also use organic granular blends or fish/seaweed emulsion. These feed slowly and improve soil health over time.

Should you fertilize daylilies in the fall?
No. Late summer after blooming is the cutoff. Fall fertilization promotes new growth that winter cold will kill, weakening the plant. Let them enter dormancy naturally.

By following these simple guidelines for when and how to fertilize, you give your daylilies the foundation they need. Consistent, appropriate feeding leads to robust plants that multiply well and reward you with an abundance of beautiful, healthy blooms season after season. Remember, the key is to work with your plants natural rhythm, not against it.