Should I Fertilize Seedlings

Should I Fertilize Seedlings?

Do you need to fertilize your seedlings? In short, the answer is yes. If the seeds are strong enough to germinate, the nutrients needed for healthy growth are usually not present in the soil. Problems with seedlings are often due to a lack of nutrients. But, as in most cases, too much fertilizer can be just as harmful as not enough. Make sure that the seedlings are not overeating and that granular fertilizer does not come into direct contact with the plant, otherwise the seedlings will be burned.

When do you have to start fertilizing the seedlings?

Should I Fertilize Seedlings?

You should start to fertilize vegetables and flowers with a light dose of fertilizer when they have their first set of leaves.  This is because the nutrients needed for the first leaves, the so-called ‘leaves’, are already in the plant’s cotyledons.

What do I mean by “real leaves”?  Aren’t all leaves the same? Not really. When the seeds germinate and leave the soil, the “leaves” first develop. Cotyledons look a little different than real leaves, which eventually turn into seedlings. The function of the cotyledons is to absorb sunlight, convert it into nutrients, and send nutrients to the whole plant until the first real leaves develop and take on their usual tasks. Cotyledons are a substitute for real leaves. The seedlings will be perfectly preserved without fertilization and without adding nutrients until this stage.

After the first set of real leaves is made, the plant needs additional nutrients. Make sure that your seedlings have at least one set of real leaves. When they do, you will be ready to start fertilizing them.

What Nutrients Do Seedlings Need?

Should I Fertilize Seedlings

Seedlings require soil-specific nutrients. The point is that when you move around every year, the plants remove these nutrients from the soil and they do not magically complement each other.

It is therefore important that seedlings are fertilized to ensure that they have access to nutrients that previous plants may have already taken from their soil.

It is also important to fertilize seedlings during soil restoration. This will allow seedlings to naturally remove what they need from the soil without additives.

This is the nutrient requirements of the seedlings:


Nitrogen is naturally rare in nature. All seedlings need it, and over the years they have learned to extract as much as possible from the soil to provide themselves with sufficient means to survive.

However, if you see how important nitrogen is, you will understand why. It helps seedlings to produce proteins that help them create new tissue and continue to build and are essential for their survival.


This nutrient is essential for seedlings because it is what they need to produce reliable root systems. Phosphorus is what encourages their roots to grow.

It also helps seedlings to produce buds, flowers, and fruit. It also helps seedlings to create healthy seeds for offspring.


We hear carbohydrates are bad. For seedlings, they’re not. Seedlings need carbohydrates for nutrition.

Well, potassium allows them to produce carbohydrates. It also helps cuttings become disease-resistant, which promotes a healthy life.


Seedlings don’t need much calcium added to the soil, but you need to make sure there is enough calcium in the soil.

The reason is that calcium is what helps to bind the soil. Calcium improves soil conditions and gives seedlings a better chance of survival.


If you were in science class, you’ve heard of photosynthesis. It’s a process that seedlings use to produce their food.

The source of food is the sun. The seedlings need magnesium to process sunlight to feed them. Without it, they will not survive.


Seedlings need protein to build and rebuild if they are damaged. Sulfur is an essential part of the protein.

Without sulfur, it could be difficult for a plant to produce protein, which could be a complete ruin of seedlings.

Each of these nutrients can be placed in your soil using different varieties of fertilizers, which we will discuss later.

However, it is important to know what your seedlings need, what they may be missing, and make sure that nutrients are either returned to the soil or applied directly to the seedlings.

How do you fertilize vegetable and flower seedlings?

Should I Fertilize Seedlings

Application of fertilizer to seedlings in two stages: the first stage is a one-time application of balanced fertilizer by transferring seedlings from the trays to larger individual pots. Secondly, weekly applications of diluted liquid fertilizer until the seedlings are ready for transplanting into the garden.

Although all vegetable or flower seedlings that produce fruit can benefit from this trick, it works very well for tomato and pepper seedlings.

A one-time application of fertilizer

If seedlings have one or two sets of real leaves, think about transplanting them into separate pots or larger cells. This process is called potting. Instead of the initial seed mixture, fill individual pots with a quality additive. Since the components of compost in pots differ from those of the seed mix, compost in pots provides more control over humidity, drainage, and nutrients for developing seedlings.

Weekly application of liquid fertilizer

After two weeks of planting, start applying liquid organic fertilizer with a high content of nitrogen (N) to the seedlings. Mix half of the proposed fertilizer concentrate in 1 gallon of water. Then feed the seedlings from below with this liquid to avoid excess water and problems with fly fungus. The nitrogen-rich fertilizer promotes new leaves and increases the height of the plants.

Other ways to feed your seedlings

From time to time you may need to spray the leaves. Dissolve a soft dose of fish and seaweed fertilizer, compost tea, or seaweed liquid in water. Fill a spray bottle with this solution. Take the seedlings outdoors and wash them with this solution. Remember to spray both sides of the leaves.

The leaves absorb the nutrients and make them available for immediate use. Root application can be used to treat a specific deficiency or to trigger a growth spurt in small seedlings.


You must understand when, why, and how to feed the seedlings correctly. Too much fertilizer can do more harm than good for seedlings, so be careful. I have had great success with the above methods. I hope that you will achieve the same results too, whether you choose organic or inorganic fertilizer. Please share your success stories or ask questions in the comments section below.

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