Best Fertilizer For Vegetable Container Gardening

This is a guide to the best fertilizer for vegetable container gardening.

Plants grown in containers don’t have access to natural nutrients in the soil.

Most soilless mixes come with enough fertilizer blended in to get through about 2 weeks.

Eventually, they will run out of nutrients as the plants absorb them and frequent watering leaches them out.

So, fertilizer is essential to the success of container vegetable gardens.

When it comes to fertilizers for container gardening, you have two choices: slow-release or timed-release granular fertilizer or liquid.

Let’s get started!

FTC Disclosure

Happy Frog All-Purpose Fertilizer is perfect for veggies, flowers, ornamentals, and all types of container gardens. Easy to use, it provides gentle slow-release feedings over time.

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Time Release Granular Fertilizers for Container Gardening

Slow-release granular fertilizers consist of water-soluble fertilizer.

It is encased in a semi-permeable resin coating.

When they come in contact with water, they will release small amounts of nutrients to the soil for use by the plant.

So, every time you water, the vegetables in the containers receive fertilizers automatically.

You can combine these granular fertilizers with the potting mix or place them on the soil surface.

Usually, gardeners use them on their annuals and flowering plants. They can supply nutrients for 3 to 4 months, depending on the amount of moisture and temperature.


  • They save time as you only need to apply them once or twice a season. It is a good option if you tend to forget to fertilize.
  • They are easier to apply than liquid fertilizers.


  • The casing will remain after they release all the fertilizer. You will wait until the vegetables tell you they need new feedings.
  • Each time you flush the pots, you wash away the nutrients.
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If you don’t want to use continuous-release granular fertilizer, you can try complete granular fertilizers.

They combine different plant, manure, animal, and mineral-based ingredients.

They are complete because they provide all three macronutrients (nitrogen, phosphorus, and potassium).

Liquid Organic Fertilizers for Container Gardening

Usually, you mix liquid fertilizers with water according to label instructions.

You apply it when you water your plants.

They will absorb the nutrients through their roots and their foliage.

Liquified nutrients are more readily and rapidly available for plant use.

Not all liquid fertilizers are created equal.

Using organic liquid fertilizers can reduce the risk of fertilizer burn and offer a more balanced nutritional intake for your vegetables.

Most natural liquid fertilizers for containers not only offer three macronutrients but also dozens of trace nutrients, vitamins, amino acids, and plant hormones.

All of them contribute to the health and vigor of your edibles.


  • Organic water-soluble fertilizers are cheaper than granular ones.
  • They will not burn.


  • Unlike the slow-release fertilizer, you need more frequent feeding.

Top Natural Liquid Fertilizers For Vegetable Container Gardening

You will find various types of liquid fertilizers on the shelf of your local nursery.

The following are some of the most popular types of organic liquid fertilizers.

If you want to create a balanced fertilizer and growth stimulant, combine the above products with other ingredients such as liquid bone meal, blood meal, feather meal, and rock phosphate.

You should apply the fertilizer to the soilless mix when it is moist.

Foliar feeding (applying fertilizer solutions through leaf pores) can supply nutrients to your plants immediately. It is especially useful for giving fast-growing plants, like vegetables, an extra boost during the growing season.

Which Type Of Fertilizer Should You Use

Look for the N-P-K ratio on the back of the packaging. N stands for nitrogen, P for Phosphorus, and K for potassium.

A fertilizer high in nitrogen or balanced fertilizer, such as a 20-20-20 blend is suitable for leafy vegetables grown in containers such as lettuce, basil, and Swiss chard.

For fruiting and root vegetables, such as tomatoes, peppers, and squash, you need a fertilizer with a higher K number such as a 15-30-15 blend. They don’t need much nitrogen.

A ratio of 3-1-2 is the best.

In reality, don’t worry so much about matching it exactly.

If you have too much N, P or K, your daily watering will wash out the excess.

When you fertilize is essential.

Different stages of growth require changes in the N-P-K ratio.

For annual plants, start them on high nitrogen fertilizer to boost growth and leaf development. Then switch to low nitrogen, phosphorous-rich solution to stimulate blooming.

Recommended Continuous-release granular and liquid fertilizers for tomatoes, fruits & vegetables.

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How Do You Fertilize Vegetables In Containers?

It does not matter if you’re making your potting compost or using a proprietary brand.

Your vegetable plants will exhaust all its available nutrients within about two weeks.

You can add a granular slow-release organic fertilizer to give an extra boost.

But even that won’t be enough for container plants.

So, you need to apply liquid feed regularly, especially for nutrient-hungry greens like brassicas or tomatoes.

Diluted with water, they provide a shot of extra nutrients for the roots to absorb.

Your plants will continue to thrive and produce high yields.

Prepare a nutrient solution and pour it over the soil mix is the easiest way to fertilize vegetable containers.

Although specific fertilization requirements vary among vegetable types, the basic guidelines for application apply to most veggies.

Every vegetable type requires specific fertilization.

But the basic guidelines for application are the same.

  1. Fill a bucket with the potting soil. Add some water. Mix it thoroughly until it is evenly moist.
  2. Use a balanced fertilizer, such as a 10-10-10 or 14-14-14 variety. Add 1/2 tablespoon of a slow-release fertilizer per gallon of soil.
  3. Blend the fertilizer and the soil.
  4. Fill the containers with the soil mixture.
  5. Transplant the seedlings into the containers.
  6. Apply liquid fertilizer at midseason.
  7. Check the label directions for the fertilizer type and the size of your container. Dilute the soluble fertilizer in the water.
  8. Water the vegetables with the solution every one to two weeks for the remainder of the growing season.

You can use a watering can to apply the solution. Alternatively, you can use a hose-end fertilizer distribution system to deliver the fertilizer automatically with the irrigation water.

Liquid fertilizers are best absorbed when the plants growing in your containers are not under stress. Do not fertilize your plants when they’re wilting or suffering from heat stress. Water them first, a few hours before feeding them, to maximize their absorption of nutrients.

How Much Fertilizer Per Plant?

The recommended amount is 100-150 ppm nitrogen. Or follow the recommendations on the fertilizer label.

It is always better to under fertilize than to over-fertilize. I prefer to use about half of what the label recommends.

Unfortunately, it is hard to determine the right numbers.

Your watering habits and the amount of rainfall in your area influence the amount of fertilizer you add.

How Often Should You Fertilize Your Container Vegetables

Once you’ve selected a fertilizer, you’ll need to apply it about once every two weeks for container-grown plants.

I assume you’re growing in a nutrient-rich potting mix that will help retain nutrients.

Feed your greens monthly with liquid seaweed to keep them healthy.

Fruiting vegetables like tomatoes in containers require weekly fertilization with the seaweed feed once a month.

You will continue to add liquid fertilizer on your vegetable garden every two to four weeks for the entire growing season.

Doing so will ensure your container-grown plants get adequate nutrition.

You can adjust the frequency of application based on overall appearance and growth.

You can also use a half-strength fertilizer solution with every watering.

Occasionally use plain water to leach the pot.

Not all container plants need regular feeding, especially lettuces or other salad leaves.

You don’t have to feed herbs at all. Lavender, thyme or rosemary grow well in nutrient-poor, dry conditions.

Fertilizer leaches out of containers each time you water the plants. Vegetables typically require weekly soluble application during dry or hot weather when you are watering daily. Apply soluble fertilizer every other week during cold weather when they are irrigated less often.


Using the right fertilizer can make or break your container gardening.

It is essential to build healthy soil for your vegetables in the containers.

Check out the following recommended fertilizers.

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