Fertilizer for Pepper Plants: What to Use and How to Use It

It takes a lot of energy and resources for pepper plants to produce their crunchy, water-filled fruits. So it’s not surprising that your plants need lots of supplemental nutrients to get that bumper crop. Like most gardeners, peppers are one of my favorite veggies to grow, and they’re pretty easy to care for- as long as you give them what they need when they need it.

Choosing the right fertilizer for pepper plants depends on the age of the plant and the soil you’re working with. Young pepper plants need high amounts of nitrogen to develop healthy green leaves. Once the plant is mature enough to produce flowers, it needs higher amounts of phosphorous and potassium. A soil test will indicate if the soil has any nutrient deficiencies that you can normalize with appropriate amendments.

In this post, I’m going over why peppers need regular nutritional boosts throughout their growing cycle, practical tips on application, and my personal favorite fertilizer for peppers plants.

Let’s get started!

What Are Essential Nutrients and Why Do Pepper Plants Need Them?

According to Alabama Cooperative Extension System, there are 16 naturally-occurring essential nutrients for pepper plants. Three of these are oxygen, hydrogen, and carbon, which your pepper plants absorb through water or air.

The other 13 come from the soil, and those are the ones you’re aiming to supply with fertilizer. They’re divided up into two groups: macronutrients and micronutrients.

Macronutrients

Macronutrients are the ones your peppers need in the greatest amounts, and they’re divided into primary and secondary categories.

Primary macronutrients are the “big three” that get most of the attention and are what make up the NPK values you see on fertilizer packages:

• Nitrogen (N): Necessary for chlorophyll production and contributes to protein formation.
• Phosphate (P): Critical for cell division and aids in healthy root, blossom, and fruit development.
• Potassium (K): Helps transfer water, carbohydrates, and nutrients; aids in energy production.

NPK values are listed as percentages. For example, a fertilizer with an NPK of 10-10-10 has 10% nitrogen, 10% phosphorous, and 10% potassium. The rest of the volume is made up of other nutrients or inert ingredients.

Secondary macronutrients are still essential to a plant’s development but to a lesser degree:

• Calcium: Aids in building strong cell walls and membranes.
• Magnesium: Essential for chlorophyll production and contributes to enzymatic action.
• Sulfur: Aids in protein production, enzymatic action, and chlorophyll production.

Most commercial fertilizers have calcium, magnesium, and sulfur included in their formula, and that’s probably going to be sufficient if a soil test shows normal levels. But if your plants show signs of a deficiency or a soil test indicates one, you can do a targeted treatment.

Micronutrients

Micronutrients are those that your pepper plant needs in trace quantities. There are seven essential micronutrients:

• Copper
• Zinc
• Molybdenum
• Manganese
• Boron
• Iron
• Chlorine

Although they’re called micronutrients, that doesn’t mean they’re any less critical for a pepper plant’s health. These elements contribute to your plant’s ability to grow healthy tissue and perform vital functions. If you have a micronutrient deficiency, you may end up with stunted growth and poor harvest.

It’s fairly uncommon to have a micronutrient deficiency in garden soil, but it’s not impossible. Organic fertilizer formulas typically contain at least some micronutrients. But you’ll have to be more vigilant with synthetic ones- they may not. So be sure to read ingredient lists carefully.

Soil Testing and pH Levels

Excessive fertilizer can alter your soil’s pH. Just like many other garden veggies, peppers of all varieties thrive in soil that’s around 6.5 to 7 (neutral to slightly acidic) on the pH scale. That’s usually not a problem for most gardeners, but when you throw off the pH from too much fertilizer, your plants can struggle to absorb and transfer nutrients.

So getting your soil tested is a critical step to make sure you’re meeting your pepper’s needs properly. You can get simple soil test kits online that will tell you the pH and primary macronutrient levels. Or you can opt for a comprehensive test that involves mailing a soil sample to a lab for analysis. I recommend SoilKit or My Soil.

Types of Pepper Plant Fertilizer

Bags of granular fertilizer and bottles of liquid formulas line garden center shelves or online sale pages. What’s the difference? Here’s what sets each one apart.

Liquid Formulas

Liquid fertilizers typically come in concentrated formulas that you mix with water. They’re easy to use because you apply them in much the same way as regular watering.

Since it’s a liquid suspension, the nutrients are spread evenly throughout the formula. This helps prevent any “hot spots,” or areas of root burn where there was too much salt. Also, the nutrients in a liquid formula are available for your plants to absorb much faster.

A subtype of liquid fertilizer is foliar fertilizer, a nutrient-rich liquid that you apply by spraying on the top or underside of the pepper plant’s leaves. This allows the plant to absorb the nutrients directly into the vascular system without going through the roots, so it’s great for a quick uptake.

But liquid fertilizers are often more expensive, especially in bulk, and you’ll go through the liquid at a faster rate. Liquids are also more vulnerable to breaking down in heat or from oxidation, so they’re harder to store for the long term. Foliar applications take more time, especially if you have a large pepper garden, and since they’re so fast-acting, you’ll have to do frequent reapplications.

Pros of liquid fertilizers:

• Easy to apply
• Even distribution of nutrients
• Quick-acting

Cons of liquid fertilizers:

• Expensive
• Need more frequent applications
• Can degrade over time

Granular Formulas

Granular fertilizers are nutrient pellets or flakes that dissolve in water and eventually mix with the soil.

In my experience, granular fertilizers are reasonably priced and easy to use. And since they’re a dry product, granular fertilizers have a stable formulation that tolerates storage without losing strength. I’ve found that they’re still effective even after a few months of sitting on my garage shelf.

Most granular fertilizers are designed to be used as a top or side dressing that you scratch into the soil before watering. But since they’re individual granules, it’s harder to get an even application around your plant. Also, the granules have to break down before the nutrients make it to the soil. So if you’ve got a plant that’s struggling with a nutrient deficiency, a granular formula won’t help right away.

Pros of granular fertilizers:

• Easy to find
• Easy to store
• Long-lasting nutrient release

Cons of granular fertilizers:

• May not evenly distribute nutrients
• Slower to get nutrients into the soil

So is a liquid or granular formula the best fertilizer for peppers? It’s really more a matter of preference, and either one will work well as long as you plan a good fertilizing routine and follow the package directions.

How to Use Fertilizer for Peppers

Like most living things, pepper plants go through a series of developmental stages from seed to mature, fruit-bearing plant. And at different stages of growth, the nutritional needs are different too.

Fertilizing New Pepper Seedlings

For pepper seeds started in regular potting mix, you won’t have to give any supplemental fertilizer until you move your peppers outside to their permanent home. That’s because pre-blended potting soil or potting mix already has nutrients mixed in.

I start all my seeds in seed-starting mix, which is a sterile soilless blend that contains no added nutrients. You will have to add supplemental fertilizer to these seedlings, but not right away.

The first leaves that sprout up through the ground are cotyledons, or seed leaves. They are not actual leaves- rather, they are embryonic parts of the seed that contain all the nutrients to support your seedling during its early days. But once the true leaves begin to grow, the stored nutrients in the cotyledons are used up, so it’s time to add more.

I recommend a liquid fertilizer diluted to 1/4 strength every 14 days for young seedlings. These young plants haven’t developed the ability to process lots of soil nutrients, so you risk giving the roots a chemical burn if you over-fertilize. You’re much better off giving less than more.

I’m a huge fan of Dr. Earth products, and I like their Liquid Solution Concentrate. It has a balanced NPK of 3-3-3, so it provides all the support your small pepper plants need. As I mentioned above, make sure to heavily dilute the fertilizer in water before you give it.

Fertilizing Older Pepper Plants

Once your pepper plants are at least 4 inches tall, have several sets of true leaves, and all danger of frost has passed for your region, they’re ready to be hardened off and moved outdoors. If you purchased your pepper seedlings from a garden center, they should be ready for transplanting outside right away.

I recommend waiting a week to ten days after transplanting your pepper seedlings before giving any fertilizer. This gives your plants time to adjust to their new home without the added stress of processing extra nutrients. And as long as you plant in a good pepper soil mix, there are nutrients available for your plant to absorb.

NOTE: Peppers in pots tend to need a little more fertilizing since they don’t have as much access to naturally-occurring soil nutrients, and the fertilizer also gets washed out more easily during watering.

Now, you’ve got a couple of options when it comes to fertilizing your peppers for the rest of the year.

I personally prefer using an all-purpose fertilizer every 2-4 weeks throughout the growing season. I like using the same fertilizer for all my plants, and I’m content to harvest enough peppers to enjoy fresh and hopefully a few to stick the freezer.

You can keep using the liquid Dr. Earth formula I mentioned earlier or something similar, but I find that it’s easier to switch to a granular formula for my older plants. Granular formulas are slower to release, so they feed the plant for a longer time. I’ve used Dr. Earth Homegrown (NPK 4-6-3) and Jobe’s Organics All-Purpose (NPK 4-4-4) with great success in the past, and I also use compost and aged manure.

But if you’re wanting to get the biggest harvest possible from your pepper plants, you’ll need to tailor your fertilizing approach to each developmental stage.

Until your pepper plant starts producing flowers, it’s in the vegetative phase. At this point, you want to supply plenty of nitrogen to power healthy green leaves and stems. Look for pepper plant food formulas with high-nitrogen NPK ratios like these:

• 10-5-5
• 6-4-4
• 9-2-7

A couple of suggestions for good vegetative fertilizers are Fox Farm Grow Big (NPK 6-4-4) and Miracle-Gro Performance Organics All-Purpose Plant Nutrition (NPK 11-3-8). Follow the package directions for how frequently to apply the fertilizer you choose.

Once you spot pepper plant blooms forming, your plant has reached a new level of maturity. Its needs change from primarily nitrogen to higher levels of phosphate and potassium. If you continue to give a high-nitrogen formula, you’ll end up with lush, leafy plants that produce few, if any, peppers.

Fox Farm Tiger Bloom (NPK 2-8-4) is one pre-made option that supplies phosphate and potassium at once.

Bone meal, aged manure, and grass clippings from untreated lawns are good sources of phosphate. For potassium, compost is a great option, particularly if it contains a lot of banana peels. Small amounts of wood ash can also help boost soil potassium. This video from The Rusted Garden does a great demonstration:

I like to give my pepper plants a dose of foliar magnesium (Epsom salt dissolved in water) every 2-4 weeks. And don’t just limit your magnesium spray to your peppers- all your garden veggies will appreciate a dose!

How to Tell If You’ve Over-Fertilized and What To Do

Minerals in fertilizers are usually in the form of salts, which can cause chemical burns to plant roots in high amounts. This is particularly a risk with commercially-produced fertilizers; natural products like compost, grass clippings, and Epsom salt are harder to overdo.

The most common signs of nutrient burn are brown spots along the leaf edges- this is where the leaf is the thinnest and the most vulnerable to damage. You may also spot a bit of leaf bubbling or curling.

If your peppers are in pots and you suspect you’ve been overzealous in your fertilizing, flush the excess fertilizer out of the soil. Give a generous watering, so that water flows freely out of the pot’s drainage holes. Wait 15-30 minutes, then repeat the drench. Going forward, cut down on your fertilizer strength and wait a little longer between applications.

Peppers growing in the ground have it easier since there’s much more soil for the fertilizer to dissipate into. Hold off on fertilizing your in-ground peppers for a while, and give a little extra water in the meantime. Then cut back on how much fertilizer you give at a time.

Final Thoughts

Fertilizing pepper plants is a key step to getting the biggest, most delicious harvest possible this year. Fortunately, it doesn’t have to be a hard or confusing process, and there are so many good ways to feed your plants the nutrients they crave.

I hope this article has answered your questions and inspired you to care for your pepper plants with confidence. But if there’s anything that’s still unclear, I’d be happy to help as much as I can. Also, if you have any tips about fertilizer for peppers that you’ve discovered, I’m all ears! Either way, please feel free to share your thoughts in the comments!