Garlic is one of the most rewarding crops to grow in the home garden. With just a bit of space, good timing, and proper care, it’s possible to produce large, flavorful bulbs that store well and enhance nearly any dish. But as the growing season nears its end, one crucial step can make all the difference between average bulbs and impressive, fist-sized harvests: the final fertilizing.

If you’ve already planted your garlic and it’s actively growing, now is the time to apply the last fertilizer of the season. This key feeding helps the plant channel energy into bulb development, ensuring maximum size and flavor before harvest.

Here’s how and when to do it properly.

Why Final Fertilizing Matters

Garlic has a unique growth cycle. In fall or early spring, it develops roots and shoots. In spring and early summer, it focuses on producing lush green leaves—which directly correlates to the future size of the bulbs. By late spring, the plant transitions its energy toward forming the bulb underground.

At this stage, applying a nutrient-rich, targeted fertilizer ensures the plant has everything it needs to support rapid bulb expansion. Skipping this step can result in smaller, less robust garlic heads.

When to Apply the Final Fertilizer

Timing is everything. The ideal moment to apply the last garlic feeding is:

  • Late spring to early summer, roughly 4 to 6 weeks before harvest.

  • When the leaves have mostly formed and the garlic has begun to thicken at the base.

  • Before the leaves start yellowing, which signals that the plant is preparing to shut down for harvest.

If you fertilize too late—after yellowing has begun—the nutrients won’t be absorbed effectively, and you may just be feeding weeds or other nearby plants.

What Type of Fertilizer to Use

For this final feeding, garlic benefits most from phosphorus and potassium, which support root and bulb development. Nitrogen is less important now, since its role in leaf growth is mostly complete.

Look for a fertilizer that’s:

  • Low in nitrogen, high in phosphorus (P) and potassium (K), such as:

    • 5-10-10 or 4-10-6 formulas.

  • Organic options include:

    • Bone meal (rich in phosphorus)

    • Wood ash or greensand (sources of potassium)

    • Compost tea or worm castings for micronutrients and a gentle boost

Avoid high-nitrogen fertilizers at this stage—they can encourage more leaf growth at the expense of bulb size.

How to Apply the Final Garlic Fertilizer

Follow these simple steps:

  1. Water your garlic bed well before fertilizing. Moist soil helps nutrients dissolve and absorb more effectively.

  2. Sprinkle granular fertilizer around the base of each plant. Stay a few inches away from the stem to avoid burning it.

  3. Lightly rake or scratch the fertilizer into the topsoil to help it reach the root zone.

  4. Water again after application to help nutrients soak into the soil.

  5. If using liquid fertilizer or compost tea, apply it directly to the soil—not the leaves—every 7–10 days until scapes begin to form.

Bonus: Remove Garlic Scapes

If you’re growing hardneck garlic, your plants will soon begin to send up curly flower stalks called scapes. While they look interesting and are even edible, they divert energy away from the bulbs.

Cutting the scapes off once they form (usually around the same time you apply the final fertilizer) will direct the plant’s full energy into the underground bulb, promoting maximum size.

Other Tips for Giant Garlic Bulbs

  • Mulch wisely. If you haven’t already, mulch with straw, grass clippings, or compost to retain moisture and suppress weeds.

  • Keep soil consistently moist until about two weeks before harvest. Dry conditions during bulb development can stunt growth.

  • Stop watering 10–14 days before harvest. This helps bulbs cure naturally in the ground and reduces the risk of rot.

Signs Your Garlic Is Ready for Harvest

You’ll know your garlic is nearing maturity when:

  • The lower leaves begin to yellow and dry.

  • The top 4–6 leaves remain green (each green leaf represents a layer of the bulb’s outer wrapper).

  • You can feel the bulb swelling beneath the soil.

Don’t wait until all the leaves have dried—that can lead to over-mature bulbs that split or store poorly.

Final Thoughts

A successful garlic harvest comes down to timing, care, and attention to the plant’s growth stages. The final fertilizing step—done at just the right time with the right nutrients—can mean the difference between small, underdeveloped bulbs and large, flavorful garlic heads you’ll be proud to store and share.

Give your garlic this last boost, and get ready for a rewarding harvest season.

jardin