Pumpkin Fertilizer [What to Use, Where to Get It, How to Use It]
In my first year growing pumpkins, I was lucky if I had one pumpkin growing per plant. I started with the right soil, but I quickly learned that without the right pumpkin fertilizer, I would never have the pumpkin harvest I wanted. Others were growing three to four pumpkins per plant and I wanted more fruit for my work.
I made my own compost and used some manure-based fertilizers, but I had never really used anything on a regular basis. And to be honest, the thought of it seemed overwhelming and scary. I didn’t want to add anything to the soil either that wasn’t organic or natural.
If you’re feeling that same way, this article is for you. I’ve experimented with many different fertilizers and in this article, I will break down when to feed your pumpkins, what to feed your pumpkins, and what pumpkin fertilizers I find work the best (and are safe).
In this article, I will cover:
How to read fertilizer labels (NPK).
The difference between liquid, foliar, and dry fertilizers.
What nutrients your pumpkins need.
What fertilizers you can use to provide those nutrients for your pumpkins.
Soil testing.
What fertilizers you can use for each stage of pumpkin growth (I use 4 different ones).
How often you should fertilize your pumpkin plants
Before we begin, I want to point out that you need to start with quality seeds, test your soil and plenty of room for the roots and vines to develop. Keep in mind the type of pumpkin you are growing too. Some pumpkins cannot grow beyond a certain size regardless of how much fertilizer you have.
For a complete list of pumpkin types and their average size, read this article: Types of Pumpkins With Pictures.
Fertilizer for Pumpkins
Do pumpkins take a lot of fertilizer? Yes. Pumpkins are heavy feeders and very hungry plants. If you thought tomatoes were heavy feeders, wait till you start growing pumpkins.
Reading Fertilizer Labels
If you read the label of any quality fertilizer, it should have three numbers on it. In the image here you can see it read 10-10-10.
Those numbers represent nitrogen, phosphorus, and potassium (always in that order). Or abbreviated, NPK (the letters for those elements on the periodic table).
Each number represents the percent of each element present. So in this example, there is 10 percent of each nitrogen, phosphorus, and potassium in this fertilizer.
This is important because depending on the stage of growth, each nutrient will affect the pumpkin differently.
There are three pumpkin growth stages and each will require a different kind of fertilizer. I know it sounds like a lot, but I’m going to make this super easy for you. Keep reading!
I typically use dry fertilizers and that is what I am going to recommend, but if you prefer a liquid fertilizer or foliar fertilizer, I’ll cover those briefly here.
Liquid Pumpkin Fertilizers
Liquid fertilizers are the easiest for your pumpkin plant to absorb because they are water-soluble. They are slightly more expensive than dry fertilizers and they require you to apply them more often because water-based fertilizers flow through the soil.
To apply a liquid fertilizer, you simply pour it into the soil just as you would if you were watering.
Many people I know apply them every time they water. This is fine if you water by hand, but if you use ollas like me, it presents a real challenge because I don’t water my plants. I let my plants take up the water when they need it through the olla. Some have told me that you can add it to an olla, but I’ve not personally tried it and I’ve always been worried that it would plug the pores of my clay.
Foliar Pumpkin Fertilizers
Foliar fertilizers are liquid fertilizers, but instead of applying them to the soil, they are designed to be applied directly to the leaves of your pumpkin plants. You simply spray the liquid on leaves and vines.
You have to be careful with these types of fertilizers because if you don’t mix them right or if you use too much, you can burn your pumpkin leaves.
Similar to other non-foliar liquid fertilizers, this type of fertilizing requires almost a weekly application.
Best Foliar Pumpkin Fertilizer
The best foliar fertilizer that I’ve found is the Pendalton Pumpkin Juice. This is a good fertilizer to use during the first stage of your pumpkin’s growth because it is high in nitrogen which will encourage your plant to grow its root system, leaves, and vines.
It has an NPK of 11-8-5 but also contains micronutrients boron, iron, and zinc for the pumpkin as well.
The reason I like this fertilizer is because it’s made specifically for pumpkins, It has a higher percent of phosphorus which helps when your plant is transitioning between stages one and two (early growth to blossoms), and it comes with an easy-to-measure bottle. You can mix it with water very easily.
If you use this fertilizer, only use it during the first 45 days of your pumpkin’s growth. After that, you will want to switch to something that has more phosphorus and less nitrogen.
Dry Pumpkin Fertilizer
Dry fertilizers are my preferred fertilizer. They are made of powder or granular minerals that you apply to the top of your soil (or a few inches underneath when you plant new seeds) and they slowly dissolve into the ground and roots of your pumpkin plant.
There are a few dry fertilizers that require measuring and mixing just like liquid fertilizers, but I don’t use those.
Here’s why I use dry fertilizers:
They are much more affordable than liquid fertilizers.
They are really easy to use and it’s hard to mess it up.
They are easy to store as they usually come compact in some type of bag or bucket.
They are hyperconcentrated so a little goes a long way.
You can find the right NPK mixture for every stage of pumpkin growth.
What to Feed Pumpkin Plants
Now that you know about the different types of fertilizers you can use with pumpkins, let’s talk about what your pumpkin really needs.
If you’re growing to maximize your pumpkin harvest this year, your plants will need nitrogen, phosphorus, and potassium to grow, but not all at the same time.
Oversized pumpkin leaf due to too much nitrogen.
Nitrogen
Nitrogen will promote the growth of vines and leaves. This is especially important during the first two months of your pumpkin plant’s life. It will promote the plant itself to grow and be healthy.
Nitrogen is an important nutrient for chlorophyll which makes the stems, vines, and leaves green. Chlorophyll is also what absorbs energy from the sun and creates sugars that feed the plant during photosynthesis.
Too much nitrogen can burn your pumpkin leaves and inhibit flower growth, so you want to keep an eye on your plants while feeding nitrogen-rich fertilizers. If you give the plant too much nitrogen it will grow more leaves and vines but may produce fewer flowers. And those flowers are what make pumpkins.
Some signs of too much nitrogen include oversized leaves, cupped leaves which are unusually deep green in color, and leaves that are burning (start to yellow at the tips).
Some fertilizers I recommend for nitrogen are:
Espoma Blood Meal (12-0-0) (Dry)
Pendalton Pumpkin Juice (11-8-5) (Liquid Foliar)
I like to use the Espoma during the first month of growing pumpkins and then switch to the Pendalton during the second month as I begin to transition to more phosphorus-heavy fertilizers.
Phosphorus
Phosphorus is essential for cell division and development of blossoms or flowers. Once you see flowers forming on your pumpkin plant, adding a phosphorus-heavy fertilizer will help it bloom more. And those flowers are what result in pumpkins later.
Too much phosphorus can cause plants to grow poorly or die because it reduces the plant’s ability to soak up micronutrients such as iron and zinc.
Some signs of too much phosphorus include yellow striping between the veins of younger leaves and stunted plant growth. If you see these signs, stop adding phosphorus-heavy fertilizers.
Some fertilizers I recommend for phosphorus are:
Espoma Organic Bone Meal (4-12-0) (Dry)
Farmer's Secret Fruit & Bloom Booster (2-15-15) (Liquid)
Potassium
Potassium helps regulate water and carbohydrates stored in plant tissue. It is part of what affects the rate of photosynthesis through the production of ATP. All of this stimulates the production of starch and protein in your pumpkins.
When the pumpkin fruit starts to appear, it is essential to feed your pumpkin plant enough potassium.
Too much potassium can cause the pumpkins to grow too fast, however, and if this happens, you risk them cracking open. It also can affect the pumpkin plant’s ability to take in micronutrients such as manganese, zinc, iron, and magnesium.
Some signs of too much potassium include the leaf tissue between the veins turning yellow or brown spots on your leaves. And of course, if your pumpkin cracks open like a splitting tomato, you probably have too much potassium in the soil.
Some fertilizers I recommend for potassium are:
Maxi Root Oragnic Seaweed Powder (0-0-17) (Foliar)
Maxi Crop Soluble Seaweed Powder (0-0-17) (Dry)
Farmer's Secret Fruit & Bloom Booster (2-15-15) (Liquid)
Depending on my pumpkin crop, I sometimes continue to use the Farmer’s Secret fertilizer to continue to feed my plants nitrogen and phosphorus, but if you have plenty of nitrogen and phosphorus in your soil, a good seaweed-based powder like the ones I use works great.
If you find that your seaweed is providing too much potassium, and you’re worried about your pumpkins cracking open, I also recommend AgroThrive's Organic Fruit and Flower Fertilizer, It has a 3-3-5 NPK and is liquid-based.
As of today, I haven’t found any great dry fertilizers for pumpkins that provide the right amount of potassium.
Fertilizing Pumpkins
For most people, keeping it easy by applying a 5-10-5 fertilizer like Espoma Garden Food throughout the entire garden season will most likely result in plenty of great pumpkins. This is a general-purpose fertilizer and if you’re just starting out, it’s a good option.
I used a 5-10-5 and a 10-10-10 fertilizer my first two years of growing pumpkins and it produced a good amount of healthy pumpkins. Some of them were a bit on the smaller side which is why I switched to using three different fertilizers for each growing stage, but I still harvested a fair amount of pumpkins those years.
Regardless of whether you use a general-purpose fertilizer or the other pumpkin-specific fertilizers I recommend, applying them every three to four weeks is a good rule of thumb.
Remember, if you use the pumpkin-specific fertilizer recommendations, make sure you use the right one for the right stage of pumpkin growth. I’ll discuss this in more detail in the next section.
Soil Tests
Conducting a soil test to determine your macronutrient levels and pH level is always a good idea too. A soil test can tell you what you’re starting with in your soil before you add anything else to it.
I prefer this Soil Test Kit from Luster Leaf. It’s quick and easy to do at home. I like that you can test each individual macronutrient individually which helps as you determine how much fertilizer to add at each stage of your pumpkin’s growth.
Another great option is to contact your local agriculture extension office or resource conservation district and have them do a soil test.
My local county conservation district office charges $20 for a soil test. I have heard that some agriculture extension offices charge up to $75 so I would see what options are available in your local area. Keep in mind that unlike the home test which can be done quickly, it will probably take around two to three weeks for an agriculture office to complete your test.
I can’t stress enough how valuable a soil test is. I do them regularly because of my composting process. Our compost never breaks down fast enough. So instead of waiting for half a year, I often bury food scraps directly in the bottom of my raised garden beds because it breaks down within weeks due to the worm activity.
Burying food scraps usually gives my garden a boost in nitrogen and other nutrients, but it’s not controlled the way it is with commercial fertilizers. Testing it lets me know what I need to add and what I don’t. Why spend extra money on fertilizers you don’t need and risk damaging your plants?
A soil test is well worth the investment and time.
Is 10-10-10 Fertilizer Good For Pumpkins
Image: Preparing my first-year pumpkin harvest. Notice that with the 10-10-10 fertilizer, some of my pumpkins were small.
A 10-10-10 fertilizer will work fine for pumpkins. It is balanced in NPK, so in theory, it provides everything you need to grow a healthy pumpkin.
I do prefer the more controlled method, which I discuss in the next section, but when I used a 10-10-10 and a 5-10-5 fertilizer, I still was able to harvest a good amount of pumpkins.
In my first year growing sugar pie pumpkins, I used these fertilizers and had five pumpkins from two plants. Some of the pumpkins were much smaller than they should have been though.
This was probably because I didn’t have enough potassium and too much nitrogen in the final stage of growth. The leaves were way too big which indicated I should have stopped all nitrogen additives and focused more on the potassium.
When I started using different fertilizers for each stage of pumpkin growth and tested my soil, I nearly doubled my harvest and my pumpkins were much larger. It was worth the investment.
Is 5-15-15 or 8-24-24 Fertilizer Good for Pumpkins
I don’t like to use these fertilizers for early-stage pumpkin growth because nitrogen is important for the pumpkin to develop vines and leaves. However, both can be used after about two months after your pumpkin seeds germinate because during those stages the potassium and phosphorus become important for flowers to form and for fruit to grow.
How To Fertilize Pumpkins
So now you know all about the different types of pumpkin fertilizers and why they’re important. In this section, let’s break down how to fertilize your pumpkin plants in each stage of growth.
Remember, it is always better to underfertilize. If you don’t feed your plant enough, nothing happens. But if you overfeed your plants, you can burn them, cause flowers to wither, or even split open pumpkins (I had this happen to me once and it was devastating).
Pre-Planting Fertilizer
It’s always best to conduct a soil test before planting pumpkin seeds. I use the Luster Leaf Radpid Soil Tester and only test for nitrogen because that is the most essential macronutrient your pumpkins will need early on.
You can get these test kits here if you need one: Rapid Soil Test Kit
If my soil needs a nitrogen additive, I buy Espoma Blood Meal (which is all nitrogen) and mix it into the top 3 inches of my soil according to the instructions.
Once I’ve done all of that, I plant my pumpkin seeds directly in the ground. Pumpkins don’t do well transplanted.
Early Growth Fertilizer
After about 1 to 2 weeks, your pumpkin seeds will germinate and you’ll see a stem with two leaves form above the ground. At this point, I add more nitrogen-heavy fertilizer for pumpkins.
It will take a month or two before you receive your first flowers. During the first two months, you want to promote healthy root, vine, and leaf development. During this early growth phase, it’s important to keep an eye on your nitrogen.
Think of your pumpkin plant like an infant at this point. If you take good care of it early on and feed it enough nitrogen, it will be able to create enough chlorophyll to absorb energy from the sun and create sugars to feed itself during photosynthesis.
It’s up to you how often you want to test your soil. But if you do test it and you have a nitrogen deficiency, make sure you add more blood meal to the soil.
If you find that you also have a phosphorus and potassium deficiency, you can use the Pendalton Pumpkin Juice which is heavy in nitrogen but also has the other nutrients.
Remember pumpkins are heavy feeders, so you’ll most likely need to add fertilizer during the growing stages.
Image: Two weeks after planting pumpkin seeds. I started applying Blood Meal.
Image: One month after using blood meal and pumpkin juice.
If use pumpkin juice, it’s rather easy to mix. You just add an ounce or two to a gallon of water and water your pumpkins with it like you would normally. I usually follow Pendalton’s recommendation and use it every 2 weeks.
If you use Espoma’s Blood Meal, you can add 1/2 tablespoon around each pumpkin plant and then water it so it starts to soak into the soil. I do this every 2 weeks as well. Just watch out for the signs of too much nitrogen that we discussed earlier.
I never use the two fertilizers together. Often times I start with blood meal and then switch to pumpkin juice after about a month of growth.
Regardless of whether you use the dry blood meal fertilizer or the liquid pumpkin juice, after about 2 months of growth, I usually stop applying both. If you’re approaching two months of growth and you don’t have any flowers developing, stop applying nitrogen.
Sometimes too much nitrogen causes overly large leaves. If you see this happen, especially after 45 to 60 days of growth, I stop adding nitrogen and switch to a phosphorus-heavy fertilizer.
Flowering Fertilizer
Sometime around 45 to 60 days, your vines should produce flowers. Once this happens (or if you don’t see any flowers at this point) you want to stop the nitrogen-heavy fertilizers and switch to a phosphorus-heavy fertilizer.
Image: Pumpkin flowered at 50 days.
Phosphorus is the element that helps provide the energy required to form flowers and fruit. If you have a phosphorus deficiency, your plant will not flower. And without flowers, there are no pumpkins.
I usually switch from blood meal to pumpkin juice around 30 to 45 days after the plant has begun growing above the soil. At around 60 days, I stop using pumpkin juice and start using bone meal. I prefer Espoma’s Organic Bone Meal. Bone meal has an NPK of 4-12-0.
If you’ve been applying fertilizer regularly up until this point, you shouldn’t need much more nitrogen. The small dose of nitrogen in bone meal should be plenty.
Similarly to blood meal, you can apply a teaspoon around the plant and water every two weeks.
Keep an eye out for yellowed edges around your leaves. This may be a sign that you have too much phosphorus. If you see this, stop applying the fertilizer.
Once you have small pumpkins starting to develop on your vines, you can start adding potassium.
Fruiting Fertilizer
Potassium stimulates the production of starch and protein. Once you start seeing fruit on your plant, you want to start feeding it more of this nutrient.
Image: Pumpkin started to fruit at 55 days.
At this point, I switch to the Farmer's Secret Fruit & Bloom Booster which is a 2-15-15 liquid fertilizer. Other people I know also use a 5-10-10 fertilizer like the Lily Miller Tomato and Vegetable Food.
The important thing is that you want to keep feeding your plant both phosphorus and potassium during this stage.
You could also keep using bone meal and add seaweed or kelp powder. The seaweed powders I recommended earlier are both 0-0-17. I’ve chosen not to do this because I don’t want to use two different fertilizers. I find it easier to use one like the Farmer’s Secret which has both potassium and phosphorus in it.
If you use the Farmer’s Secret Bloom Booster, it’s super easy. You can add 1 teaspoon to 2 gallons of water and water your plants like you would normally. It’s a little pricey, but it’s concentrated and goes a long way.
I feed my pumpkin plants every 2 weeks at this stage.
Keep an eye on your pumpkins because too much potassium can cause them to grow too fast and split open. If this starts to happen to you, stop applying fertilizer.
How Often to Fertilize Pumpkins
Because pumpkins are heavy feeders, I fertilize my pumpkins every two weeks.
For the first two months, I feed them blood meal or pumpkin juice every two weeks.
Once flowers start to show up, I feed my plants either pumpkin juice or bone meal. I usually feed them every two weeks.
And once fruit starts to develop, I start using the fruit and bloom booster. I feed them every two to three weeks at this point depending on how fast my fruit is growing.
When to Stop Fertilizing Pumpkins
Do not fertilize pumpkins during a heat wave. All pumpkin fertilizers contain salts that can dry out the soil with extreme heat. It’s best to wait until the threat of heat has passed and then resume your fertilizer schedule.
Pumpkin Fertilizer Products I Use and Recommend
Soil Test Kit
Knowing what is in your soil helps you determine what fertilizer to use and how much to use. I use and recommend the Luster Leaf Soil Test Kit.
Seeds
If you don’t have quality seeds, all the fertilizer in the world won’t make a difference. I use and recommend Botanical Interests Pumpkin Seeds.
Composter
I’ve tried a couple of these for dry compost and my favorite and most durable has been Greenes Cedar Wood Composter. I only use this for yard waste and grass clippings. I wouldn’t put any food scraps in here unless you want to attract wildlife.
What I like about them is you can start with one and add on as many as you want later. Or you can start with all three.
Fertilizers
Here is a list of all the pumpkin fertilizers I use and recommend.
Pumpkin Fertilizer Conclusion
Pumpkins are heavy feeders and need nitrogen, phosphorus, and potassium, but at different stages of growth.
Fertilize pumpkins every two weeks with a nitrogen-heavy fertilizer for the first two months.
After two months, switch to a phosphorus-heavy fertilzer to encourage blooms.
Once you see fruit develop (pumpkins), use a phosphorus and potassium-heavy fertilizer.
Use soil tests and keep an eye out for signs of too much NPK (nitrogen-phosphorus-potassium) and adjust accordingly.
Cole Sperry has built an extensive suburban garden at his home in Riverside, CA. He is a proponent of sustainability and reducing our carbon footprint, as well as eating closer to what nature intended. Today Cole can be found in his backyard garden experiementing with new gardening techniques and buidling garden memories with his children.