When To Apply Fertilizer To Vegetable Gardens - Backyard Boss
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When To Apply Fertilizer To Vegetable Gardens

Fertilizing your garden can be a tricky process, and a mistake can be very punishing, sometimes even fatal, to your plants. One of the most common mistakes people make is fertilizing at the wrong time.

When to apply fertilizer to vegetable gardens is a very important aspect of caring for them. Learn the basics of fertilizing your gardens.

What is a Fertilizer?

David Thuell, Soil Tester at work. Clay indexing at Materials Laboratory, Herston, October 1989
Image credits: Queensland State Archives via Creative Commons

Plants require a lot of nutrients to survive and thrive. The four most important nutrients are nitrogen, phosphate, potassium, and sulfur. In the same way, we need a balanced and consistent diet to grow and stay in good health, so do the plants. However, after each season, crops tend to exhaust the soil by using up all the nutrients, which results in a lack of certain nutrients. To prevent your plants from dying, you will need to replenish nutrients, usually by adding fertilizers.

Of course, before you proceed to use fertilizers, you should always first test your soil. This test can give you a lot of information about the nutrients your soil lacks. Most people assume their soil lacks nutrients, so they add fertilizers without finding out which particular nutrient the soil lacks. Too much fertilizer can also harm your plants.

For example, if your soil doesn’t lack nitrogen and you still fertilize it with nitrogen, your plants will start producing stalks and leaves in excess, but the root structure will remain the same. Remember, plants need a specific amount of nutrients, and if they take in larger amounts, the effect could be the opposite.

When To Apply Fertilizer To Vegetable Gardens

To understand when to apply fertilizer to vegetable gardens, you have to take into consideration what type of crops you are growing first.

Edible Crops

Herbs growing in pot on table top with 2 clear glass jars behind
Image credits: cocoparisienne via Pixabay

When it comes to edible crops, fertilize them in the spring. You should apply and mix the fertilizer with the garden soil first and then plant your edible crops. Even if you have somewhat of a quick hand and have already planted your plants or put in your seeds, you can carefully put in granular fertilizer. You don’t need to go too deep – only about 3-5 inches. After adding granular fertilizer, gently water it in. If you’ve already planted your seeds or seedling, don’t use a liquid fertilizer, as it can burn the roots of younger plants.

Perennial Flowering Plants

red and pink petunias in a pot
Image credits: congerdesign via Pixabay

You can fertilize perennial flowering plants before they start to grow in the spring. Wait until a week has passed from the last frost. Gardeners usually wait a week because this time serves as insurance – it means that the risk of fragile young plants dying to frost is minimal.

Different Plants Have Different Needs

Even though many people believe that spring application is a rule that always has to be followed, this is not exactly the case. Different plants have different needs, so the key to growing them properly and giving you a good yield is understanding what they need the most during their most rapid growth. For example, long-season crops, like corn and squash, grow rapidly in the middle of the summer. This is why many gardeners apply a little fertilizer to start the plants up when seeding, then add a bigger amount in the first weeks of summer.

Another example of a different fertilizing cycle is blueberries and strawberries. Fertilizer is most beneficial to blueberries when it is added early in the season. Strawberries, on the other hand, get the most out of being fertilized after their harvest. Vegetables such as potatoes and tomatoes need more fertilizer in the middle of the season since they have already exhausted the nutrients. When you see flowers on your tomato plants, put in a low-nitrogen fertilizer if you want to get more fruit rather than foliage.

What to Keep in Mind When Applying Fertilizer

When in Doubt, a Soil Test is an Answer

soil in bag for test
Image credits: microgenvia Canva

As mentioned earlier, soil tests are a crucial part of choosing the proper fertilizer for your garden. A good time to do a soil test would be in the autumn, so you have enough time to get the results back to react accordingly. Soil tests are an important part of gardening since under, or over-fertilization can harm your plants. You can use a soil test kitDIY with household items, or get professional help. If you decide to get professional help, know that it takes anywhere between 7 and 14 days to receive the results of your soil test. Of course, this may vary, but keep in mind when you seek professional help, the results aren’t instantaneous.

Amount of Fertilizer You Need

Hands with compost and dirt
Image credits: melGreenFR via Pixabay

When you buy a bag of fertilizer, pay close attention to a combination of three numbers. They represent the three crucial nutrients for plants – Nitrogen (N), Phosphorus (P), and Potassium (K). The numbers you see will refer to the percentage of weight for each nutrient inside the bag. The rest is a filler so that the fertilizer can be applied easily. Of course, there can be other nutrients in there, such as calcium, iron, manganese, and magnesium.

When starting your vegetable garden, fertilize your plants with three parts nitrogen, four parts phosphorus, and four parts potassium (3-4-4). However, if you want to grow tomatoes, use a 3-4-6 fertilizer since it contains calcium, which helps against blossom-end rot. Phosphorus is crucial at the beginning – it is what plants need to develop their roots and grow. Potassium helps plants fight off disease. The reason nitrogen, which is the first number, is the lowest is because it helps the growth of leaves and not vegetables.

Remember, most vegetables require a nitrogen boost only after they have grown up or have started to yield. Adding too much nitrogen, in the beginning, can slow down the growth, resulting in lower flowering and yields.

Processed vs. Organic Fertilizer

Processed fertilizers have a lot of advantages and disadvantages. The primary reason people use them is that they replenish the soil’s nutrients faster. With processed fertilizers, you can choose the particular nutrient you want to replenish. Processed fertilizers are also easy to solute in water, which makes them easy to absorb by the plants. Although chemical fertilizers promise a plentiful yield, they’re not good for the environment and can even be harmful to animals. Using chemical fertilizers often will degrade the natural fertility of the soil.

On the other hand, we have organic fertilizer. Organic fertilizers improve the soil’s structure, which results in better water retention. Organic fertilizers are eco-friendly since they don’t pollute water, don’t pose a threat to animals, and bring up biodiversity by 30%. You can even learn to make homemade garden fertilizer!

Frequently Asked Questions

1. When to apply 10-10-10 fertilizer to a vegetable garden?

When you see new growth in early spring, apply the first dose. You can do that every month, but if the plant growth is slow, you can apply a dose in the fall. Remember to add these doses only after the risk of frost has passed, i.e. a week from the last frost.

2. What kind of fertilizer do tomatoes need?

Tomatoes prefer fertilizer high in phosphorus, so ratios like 3-4-6 or 4-7-10 do justice to these plants. As with any plant, don’t over-fertilize your tomatoes. You risk burning the roots and damaging the plant altogether.

3. When is the best time to fertilize vegetable gardens?

The best time to fertilize any plant is during the evenings when the sun is setting. You can even fertilize your plants after a rain. If you fertilize your plants before the rain, they will wash away, leaving no nutrients for the soil to absorb. If you fertilize your plants when the sun’s bright, the fertilizer can “bake” and either lose its efficiency or burn the plants due to concentrated amounts of nutrients.

4. What are the signs of over-fertilization?

While there are many signs of over-fertilization, a common one is that over-fertilization can cause excess leaf and stem growth with little to no flowers, i.e. stunted growth. Over-fertilization could also be the reason why your vegetable garden is struggling. For example, your tomato plant may look lush, but it won’t flower or produce tomatoes. The plant may look healthy, but its roots won’t have developed. Undeveloped roots won’t be able to absorb nutrients from the soil.

5. How to fix over-fertilization?

The only way to fix over-fertilization is to flush out the soil by watering it as much as it can hold for a few days. If your soil is over-fertilized, don’t allow the water to trickle off, as this toxic water can pollute other areas and cause damage to the environment. It can also cause harm to animals who consume this water if it remains as a puddle. If you spot a puddle, mop it up before splashing clean water to eradicate toxicity.

In Summary

Fertilizing your vegetable garden can be a tricky process, but if successful, it can increase your yield drastically. While most vegetables require fertilizing in early spring, some need special attention and different conditions, so make sure you know them well beforehand. Hopefully, this article has helped you in your endeavor to fertilize your vegetable garden. If there’s anything more you’d like to know, ask us in the comment section down below!

Happy Gardening!