13 Garden Veggies That Need Extra Fertilizer

Heavy feeder veggies are like pigs; they eat and eat to no end! They’ll benefit from regular fertilizer applications during the growing season. Some are perennials, some are annuals, and all are delicious crops for the home garden.

When you feed veggies properly, you boost their ability to resist pests, diseases, and poor growing conditions. Healthy crops are resilient and vigorous. Give the plants what they need, and they’ll reward you with more fruit than you can manage. 

Without further ado, here are the 13 most common heavy-feeding veggies that need extra fertilizer. By the time you notice they’re hungry, it’s likely too late! Knowing which ones need extra fertilizer will help you prepare the garden ahead of time. 

Double Yield Cucumber

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Double Yield Cucumber

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Tropical Sunset Pole Cherry Tomato

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Tropical Sunset Pole Cherry Tomato

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Green Globe Improved Artichoke

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Green Globe Improved Artichoke Seeds

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Artichoke

	botanical name Cynara cardunculus ssp. cardunculus
	sun requirements Full sun
	height 3-5’
	hardiness zones 7-10

Artichokes are perennial crops with edible flower heads. The unopened blossoms have scales with savory flesh that you can tease out with your teeth. Dip them in mayonnaise, ranch, sour cream, or your favorite sauce.

In the garden, artichokes are tough plants. They’re drought-tolerant, easy-growing, and tall. Though they’re vigorous, their rampant growth requires extra nutrients via organic matter or fertilizer. Give your plants monthly doses of high-nitrogen fertilizer four weeks after transplanting them into the garden. 

Asparagus

	botanical name Asparagus officinalis
	sun requirements Full sun
	height 3-5’
	hardiness zones 2-9

The more asparagus you have, the more fertilizer you’ll need! Asparagus plants, like artichokes, need more nutrients than your other crops. They benefit from regular feeding and watering after the harvest period is over. With enough nutrients, they’ll produce spears for decades to come.

Asparagus is a tricky plant to harvest. You’ll need to let it grow without harvesting for a year or two after planting crowns, and three years after planting seeds. After the growing period is over, you may pick spears for a month or two in spring. Then, let them grow from June until fall without harvesting them.

Cardoon

	botanical name Cynara cardunculus
	sun requirements Full sun
	height 3-6’
	hardiness zones 7-10

Cardoons are the parents of artichokes. They grow similarly, with leafy fronds and bulbous flower clusters, though growers use them for their edible stalks instead of their blooms. The fleshy, spongy stalks taste like artichoke hearts, and they roast well with other veggies. 

If you’re growing cardoons as ornamental plants, you won’t need to feed them. They’ll grow well in fertile soil with plenty of organic matter. 

If, however, you’re growing cardoons for their edible stalks, you’ll want to feed them monthly helpings of fertilizer with high doses of nitrogen. Do so after the leaves emerge in spring for existing plants, and a month after transplanting for new ones. 

Celeriac

	botanical name Apium graveolens var. rapaceum
	sun requirements Full sun
	height 2-3’
	hardiness zones 3-6

Celeriac is a cultivated variety of wild celery that grows a large, edible root instead of stalks. The root has a unique, celery-like flavor that works well in roasts, mashes, and sautés. To swell and bulb up, the plant needs a steady supply of nutrients over a long, mild growing season. 

Feed this veggie with extra organic fertilizer every two to three weeks while the plant is actively growing. The more you feed it, the more likely it is to produce a sizable harvest.

Celery

	botanical name Apium graveolens var. dulce
	sun requirements Full sun
	height 10-30”
	hardiness zones 3-6

Celery is another cultivated variety of wild celery, though the cultivated version is more flavorful, tender, and mild than the wild one. Varieties like ‘Utah’ provide reliable harvests in regions where celery struggles. Start seeds indoors 10 weeks before the last frost date, then transplant them outdoors after the date. 

After transplanting into the garden, celery benefits from fertile soil. This veggie may need extra fertilizer in nutrient-poor sites. Fertilize your crop every two to three weeks with a liquid organic fertilizer. Mix it in a watering can or irrigation system and apply it when you water.

Corn

	botanical name Zea mays
	sun requirements Full sun
	height 5-8’
	hardiness zones 2-11

Corn is a moderate feeder, meaning it needs more than the average crop but less than heavy feeders. It’s a quick-growing annual that thrives under summer heat, so long as you water it regularly. Plant seeds directly in the ground two weeks after the last frost date, and sow seeds successively every two weeks for a bountiful harvest. 

Feed your corn twice during the season using a high-nitrogen fertilizer. Apply one dose when the seedlings are a foot tall, and another when they’re two feet tall.

Cucumber

	botanical name Cucumis sativus
	sun requirements Full sun
	height 8″-8′
	hardiness zones 2-11

Cucumbers are moderate feeders, like corn plants. They sprout off of long, vining stems that stay low to the ground. When given support, the twining stems may reach lengths of eight feet or longer! For lush leaves and succulent cucumbers, feed the plants twice during the warm months.

To start, apply a balanced fertilizer after the vines begin growing with speed and vigor. Then, add another regular dose a month later when blossoms appear and cucumbers begin to form. 

Eggplant

	botanical name Solanum melongena
	sun requirements Full sun
	height 2-4’
	hardiness zones 9-12

Eggplants are close relatives of tomatoes and peppers; they’re all in the same family, Solanaceae, also known as the nightshade family. These veggies grow best when they have access to moderate amounts of nitrogen, phosphorus, and potassium, as well as secondary nutrients and micronutrients. 

Give eggplants regular doses of half-strength fertilizer. Dilute a balanced, liquid solution with water, then apply it every two weeks while watering your plants.

Melon

	botanical name Cucumis melo
	sun requirements Full sun
	height 6-9’
	hardiness zones 2-11

Close relatives of cucumbers, melons are sweet fruits that sprout off long, climbing vines. Unlike cucumbers, melons tend to climb on their own when given support. They’re perfect for yards with vertical space. Give them a trellis, arbor, or stake, and they’ll reach towering heights.

For the most melons and vigorous growth, add extra veggie fertilizer every six weeks. Place it a few inches away from the stems to avoid burning the plants. Dig in a powdered blend, or water in a liquid one. 

Onion

	botanical name Allium cepa
	sun requirements Full sun
	height 12-18”
	hardiness zones 5-10

Onions are a longtime favorite veggie crop across all 50 states. They’re pungent, sweet, and incredibly flavorful. If you’re growing a kitchen garden, there’s a high chance you have onions in the dirt.

To grow the biggest, most bulbous onions ever, fertilize the ground around them regularly during the warm, sunny months. Use a well-balanced blend with low levels of nitrogen, and add it often in small doses. Weekly helpings are beneficial early in the season to get long, leafy growth from the tops. 

Pepper

	botanical name Capsicum spp.
	sun requirements Full sun
	height 1-6’
	hardiness zones 9-11

Whether you like them sweet or hot, peppers are delicious, nutritious, and colorful. They’re essential in the garden if you like making salsa or spicy sauces. Eat sweet peppers fresh off the plant, or prepare spicy ones in meals and preserved goods.

Peppers fare well without extra fertilizer if they’re growing in fertile soil. Sites with plenty of compost, leaf mold, or other organic mulches may already contain sufficient nutrients for your pepper plants. If you’re unsure, take a soil sample to a local university to test how fertile or nutrient-poor it is. 

Squash

	botanical name Cucurbita spp.
	sun requirements Full sun
	height 1-25’
	hardiness zones 3-11

Summer and winter squashes fill late-summer gardens with their wonky-looking fruit. Some are perfect and cylindrical while others have knobs and ridges. Flavors range from rich and creamy to sweet and savory. 

For maximum fruit production and minimal leaf growth, fertilize with a balanced organic type every three or four weeks when the vines are actively growing. Avoid adding too much nitrogen, as it’ll cause ample leaves at the squash’s expense.

Tomato

	botanical name Solanum lycopersicum
	sun requirements Full sun
	height 1-10’
	hardiness zones 10-11

Beginners and longtime gardeners all grow tomatoes! Though they’re technically fruits, tomatoes are lumped with veggies because they grow like our favorite crops. They’re perennials in warm regions and summer annuals in cold ones. Start seeds early indoors, then transplant the seedlings a week or two after the last frost in spring.