10 Best Fertilizer for Cucumbers for Bigger Yields & Better Growth

If you want optimal growth this year, make sure you get a good cucumber plant fertilizer!

Cucumbers are a quintessential fruit for your vegetable garden, and the plants often produce large harvests. If you want to ensure your plants produce plenty of cucumbers – who doesn’t? – you’ll need to make sure you use the best fertilizer for cucumbers.

I have to tell you a secret.

I never used to fertilize my plants – seriously.

For years, I assumed my crops grew fine without fertilization, but when I began to fertilize regularly, I realized I missed out and skipping this step is a no-no. Your plants will thrive with the right fertilizers and a healthy feeding schedule.

Cucumber plants are heavy feeders, requiring higher amounts of potassium and phosphorus than nitrogen. Understanding what these plants need before picking out a fertilizer is essential, so let’s look at the ideal nutrients for cucumber plants, how to pick out a fertilizer, and my picks for the best cucumber fertilizers.

Related: 6 Best Fertilizer for Cabbage: The Key to Huge Heads!

What Nutrients Do Cucumber Plants Need?

Cucumbers have different nutrient requirements than many other vegetable plants you may grow in your garden. These plants require less nitrogen and more potassium and phosphorus.

If you feed your cucumber plants fertilizers high in nitrogen, it will lead to excess green growth, taking energy away from the fruit. Nitrogen-fed cucumbers send their energy into growing more vines, leaves, and shoots, when we all know we want more blossoms and fruits.

Another problem with putting too much nitrogen into the soil near cucumbers is excess nitrogen causes cucumber flowers to not open. That means the fruiting is even further reduced.

So, make sure you stick to lower nitrogen fertilizers!

It’s also to crucial to pay attention to your soil type. Sandy soils will allow nutrients to seep out quickly, so you will need to fertilize more forte. Clay soil, on the other hands, hold onto nutrients for longer, so spread out your fertilization schedule.

How to Pick the Best Fertilizer for Cucumbers

Picking the right fertilizer for cucumbers matters. The wrong fertilizer will harm or potentially kill your plant. Too much of a good thing often becomes a bad thing, so selecting one that will promote larger cucumber yields and improve the overall health of the plants and the soil are ideal.

Let’s take a look at how you should make a choice between all the awesome fertilizers on the market.

Related: 9 Super Cheap Fertilizers You Have at Home

NPK Fertilizer Ratio

The first, and most important, qualification for any fertilizer is the NPK ratio, as well as any supporting micronutrients, trace elements, and beneficial bacteria in the fertilizer. Basically, this indicates what the fertilizer will provide to your plant.

All fertilizers have their NPK ratio displayed on their container as three numbers. NPK stands for nitrogen (N), phosphorus (P), and potassium (K). So, if you grab a fertilizer labeled 3-4-6, it means that it contains 3% nitrogen, 4% phosphorous, and 6% potassium.

Selecting the right NPK is crucial for all plants. Think about where you grow your plants; cucumbers grown in containers benefit from a lower overall NPK rating, such as a 2-3-6, but plants grown in the ground receive more nutrients with a 5-10-10 or 20-20-20 fertilizer.

Typically, you want a fertilizer for cucumbers that is lighter on nitrogen and high in potassium and phosphorus to avoid too much leaf growth. Too much nitrogen will lead to more greens growing and fewer fruits.

Granular vs. Liquid Fertilizer

Next, think about the application method you prefer. Both granular fertilizers and liquid fertilizers have advantages to consider.

Liquid fertilizers allow the nutrients to reach the roots of the plants much faster, so they uptake through the plant rapidly. So, if your plant needs a quick fertilizer boost, liquid is often the way to go, but beware that overfeeding the plants may burn the plant roots.

Here are some other advantages of a liquid fertilizer.

• Cost effective
• Combines watering and fertilizing to maximize your time in the garden
• Gives you more control over how much the plants receive
• Great for those with shorter growing seasons
• Tend to be less expensive

Granular fertilizers generally are slow-releasing, so they provide a steady amount of nutrients to your plants over several weeks or months. This means you have to apply fertilizer less often, but if you need results quickly, granular wouldn’t be the best choice.

• Time saving since you have fewer applications needed
• Won’t leach into nearby water sources
• Gives consistent nourishment
• More options available

I keep both on hand because I know that I may need them for different circumstances.

Organic – Yes or No?

Some cucumber fertilizers are organic, and others aren’t. It’s up to you to decide if you want organic only; some fertilizers contain chemicals that may be hazardous and not safe around your pets or kids.

Organic fertilizers are made from organic compounds and ingredients, which absorb easily into the plants. These are safe and effective, but you may not see the dramatic results as non-organic, chemical brands provide.

Organic fertilizers tend to be less labor intensive since many non-organic types require more than one fertilizer to be mixed and have specific requirements or timing needed. So, if you want to a relaxed schedule, organic may be for you.

However, if the yield is your biggest factor, a chemical fertilizer may be your best bet!

Price

The price of fertilizers vary greatly. If you want to save money, granulated or powder fertilizers are great; they mix into the soil and require reapplications every month or so.

No matter your budget, you’ll find something that works for you and your garden.

Safety

Safety should always be a concern when picking a fertilizer for cucumbers. If you have kids or pets – I know I have both! – you don’t want something that may harm them if they are in your garden during application.

Kids love to wander gardens; we don’t want them exposed to anything dangerous.

If you don’t want to worry about wearing gloves and safety glasses, organic fertilizers will be at the top of your list. Many non-organic varieties state that you need to wear safety gear and follow their safety protocols during application.

10 Best Fertilizer for Cucumbers

1. Jobe’s Plant Food Vegetable & Tomato

Let’s start with one of my favorite fertilizers – Jobe’s Organics Vegetable & Tomato Fertilizer. Jobe’s is a huge name in the fertilizer world, and this formula is great for cucumbers, as well as a range of other plants in your veggie garden.

This fertilizer is a 2-5-3 ratio, so it’s low in nitrogen, exactly what cucumber plants need. It’s easy to apply with dissolving granules.

Jobe’s created this fertilizer from:

• Bone Meal
• Poultry Manure
• Sulfate of Potash

This contains Jobe’s Biozome, a group of microorganisms that help break down materials for faster results. It helps to improve the overall health of the soil in your garden and the soil conditions. Beneficial bacteria also helps your plants resist disease and pests!

It’s safe to apply this fertilizer multiple times in the growing season. It’s suggested to apply before planting and every two to three weeks during the growing season. Their packaging gives clear instructions on how to use.

You can use this organic fertilizer near your pets and kids; it’s biodegradable, sustainable, and safe!

The only downside is that this fertilizer isn’t for hydroponics use, and some say that it is a bit pricey. However, I watch for sales – I got several bags 50% off on Amazon this season. You also will find this brand at your local stores, so watch for mark downs.

✅ PROS ✅

• Organic & OMRI Listed
• Easy to Apply
• Low in Nitrogen
• Adds Beneficial Bacteria to the Soil
• Improves Soil Health
• Great Price

❌ CONS ❌

• Not for Hydroponic Use

2. Epsoma Garden-Tone Granules Organic Plant Food

Epsoma is a popular brand of fertilizer you may find at your local stores. I know both Walmart and Rural King, two of my local stores, carry this brand during the growing season.

Their Garden-Tone is a slow-release, granular fertilizer that is great for cucumbers an other vegetable plants that grow well in nitrogen-rich soil. It is lower in nitrogen than other fertilizers on this list, but that’s ideal since too much nitrogen is often bad during fruiting.

The NPK ratio is 3-4-4 for this plant food.

Epsoma formulated this fertilizer with 15 essential nutrients and fortified it with Bio-tone technology. Bio-Tone creates a better environment for beneficial microbes and microorganisms in your garden.

If you take a look at the ingredients, Epsoma says they use no fillers and all organic materials. The ingredient list includes things such as:

• Feather meal
• Bone meal
• Poultry manure
• Sulfate of Potash
• Alfalfa meal

The list also has added nutrients like 5% calcium, 1% magnesium, and 1% humid acid. These are all essential nutrients; magnesium contributes to photosynthesis of the plant, and calcium improves plant cell formula.

Epsoma recommends you apply this fertilizer before planting and then apply it every month throughout your growing season. It’s best to place this fertilizer along the drip line, two to three inches away from the stems.

✅ PROS ✅

• Available in Many Stores
• Slow Release Formula
• Organic
• Safe for Kids and Pets
• Contains Extra Nutrients
• Works for a Variety of Plants

❌ CONS ❌

• Strong Odor
• Non-Vegan

3. Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer

Here’s another brand I found at my local Walmart – Dr. Earth – and their organic fertilizer has high ratings. Gardeners rave about the effects they see after application when used as either a top dressing or a water-soluble tea.

Their Tomato, Vegetable & Herb Fertilizer contains probiotics and seven beneficial microbiotics, all selected to help the plants metabolize nutrients better. This helps increase the size of your cucumber yield – noticeably.

Dr. Earth is an excellent option if your cucumber plants grow in nutrient-rich soil after applying compost before planting. The NPK ratio is 4-6-3, and since it has a higher phosphorus ratio, it’s great for helping your plants provide you with more fruits.

The ingredients for this fertilizer include:

• Fishbone Meal
• Feather Meal
• Bone Meal
• Fish Meal
• Kelp Meal
• Rock Phosphate

This is a people and pet-safe fertilizer, so you never have to worry that it will harm those you love. All you have to do is add 1 1/2 cups of fertilizer to the soil before planting and reapply every two months.

✅ PROS ✅

• Great Value for Your Money
• Organic & Non-GMO
• Includes Probiotics & Seven Beneficial Microbiotics
• Easy to Apply
• Enriched with Minerals

❌ CONS ❌

• Doesn’t Contain Magnesium
• Strong Odor – May Attract Other Animals

4. Joyful Dirt Premium Concentrated All Purpose Plant Food & Fertilizer

No, this isn’t a bottle of seasonings; it’s an all purpose fertilizer that works for all sorts of plants you might have in your garden. It’s a multi-use formula that is easy to apply ad nutrient dense to support your rapid plant growth.

This fertilizer comes in a small shaker, so it’s ideal for those with small gardens or limited space where they grow cucumbers. It also means you don’t have to deal with heavy bags and mixing different fertilizers together.

All you do is shake it out!

The NPK is 8-1-5, so it does have a higher nitrogen content. I would avoid using this after the first flowers develop on the plant since you don’t want too much energy going to the leaves and vine development.

Joyful Dirt added mycorrhizae, which reduces the need for extensive watering. Mychorrhizae allows plants to absorb nutrients at a rate of 100 times faster than normal. This increases the overall plant vigor.

Joyful Dirt is safe to use around kids and pets, so don’t worry – you can even use it for indoor gardens!

✅ PROS ✅

• Organic
• Easy to Use
• Safe for Kids & Pets
• Good for Indoor & Outdoor Gardens

❌ CONS ❌

• Expensive
• Small Amount – Only 3 Ounces

5. Down to Earth Organic Vegetable Fertilizer

Down to Earth is one of my favorite brands of fertilizers; I have several of their varieties like their alfalfa meal and bone meal.

One of the best cucumber fertilizers is their organic vegetable fertilizer that is an equal ratio with a 4-4-4 NPK rating. It’s formulated to work well with compost-amended soil, so if you add compost to your soil before planting (hint – YOU SHOULD), this works great in your soil.

It has some great ingredients, including:

• Fish Bone Meal
• Alfalfa Meal
• Feather Meal
• Potassium Sulfate
• Kelp Meal

Down to Earth created a granular fertilizer that works by sprinkling it directly onto the soil, but the directions also say you may use as fertilizer tea as well. The fertilizer is gentle and mild enough that it won’t burn the roots or foliage of the plants.

Since you should fertilize cucumbers regularly, this is great. It also contains calcium, magnesium, and iron, all minerals your plants need.

Down to Earth recommends applying 1/2 cup per square foot of growing space, working the granulars into the top layers of soil every two weeks.

✅ PROS ✅

• Equal NPK Ratio: 4-4-4
• Great with Compost Amended Soil
• Mild Enough for Regular Feedings
• Contains Needed Minerals
• Safe for Kids & Pets

❌ CONS ❌

• Pricey

6. MasterBlend Tomato & Vegetable Fertilizer

So far, most of these fertilizers are for small scale gardeners, but if you grow cucumbers on a large scale – perhaps a gamer – then MasterBlend is an excellent option for you to consider.

MasterBlend Tomato & Vegetable Fertilizer is a synthetic fertilizer, used in commercial farms, and it has a reputation for increasing your cucumber yields. This water-soluble fertilizer is safe for in-ground gardens and hydroponic gardens.

The NPK ratio is 4-18-38, so it’s quite low in nitrogen and higher in potassium and phosphorus. This ratio is perfect for growing cucumbers! MasterBlend added other nutrients to the blend as well, including:

• Magnesium
• Iron
• Zinc
• Boron
• Copper
• Manganese

All of these are great for the overall health of your plants, so it’s easy to see why it’s a highly rated option.

The only downside to MasterBlend is that the fertilizer must be mixed with Epsom salt and calcium nitrate for balanced plant nutrition. MasterBlend says the ingredients must be mixed separately to the fertilizer to avoid any reactions. Reviewers say that mix the Epsom salt before applying calcium nitrate.

This is quite a disadvantage to this product; not everyone wants to do the extra work.

Also, it’s non-organic, so it’s not kid or pet-friendly. Wearing safety gear like gloves and masks are ideal when handling this product.

✅ PROS ✅

• Great for Large Scale Gardeners or Farmers
• Safe for Hydroponics & In-Ground Gardens
• High in Phosphorus & Potassium
• Contains Many Nutrients
• Water-Soluble Formula

❌ CONS ❌

• Synthetic
• Not Kid or Pet-Friendly
• Requires Extra Ingredients for Optimal Performance

7. Down to Earth Organic Vegan Fertilizer

Another awesome fertilizer for cucumbers by Down to Earth is their 3-2-2 Organic Vegan Fertilizer. This is great for vegan and vegetarian gardeners because it contains no animal products or any by-products. Down to Earth uses a blend of plant-based, nutrient-ingredients like:

• Alfalfa Meal
• Soybean Meal
• Kelp Meal
• Rock Phosphate

This fertilizer is mild, but it is heavier on the nitrogen. It’s great for giving your plants small boosts throughout the growing season or right when you plant.

It contains essential nutrients, all derived from plant materials, that help your plants grow to their maximum potential. Your plants also receive doses of calcium and magnesium with this fertilizer.

Apply 1-2 TBSP of this fertilizer into each hole when you plant your cucumber seedlings. It’s safe to reapply fertilizer every month during the growing season.

✅ PROS ✅

• Mild 3-2-2 Ratio
• Suitable for Vegan Gardening
• Safe to Apply Monthly
• Contains Calcium & Magnesium

❌ CONS ❌

8. FoxFarm Big Bloom Liquid Concentrate

FoxFarm is slowly becoming a popular line of fertilizers; you may be able to find their products in a store near you. They sell different formulas, which helps them stand out since they have fertilizers targeting different needs for your plants.

FoxFarm Big Bloom is an organic fertilizer, created to produce big blooms in your fruit crops. The goal is to encourage more fruit production and improve the overall quality of your harvest. Gardeners say this concentrate helps improve the overall flower and fragrance of the fruits.

The NPK ratio is 0 – 0.5 – 0.7, so it contains no nitrogen and only small amounts of phosphorus and potassium. It’s fortified with a biologically alive formula that improves the soil health, and it’s enhanced with bat guano and earthworm castings. Overall, this fertilizer is great for creating a nutrient-dense soil environment for your plants.

✅ PROS ✅

• Organic & OMRI-Listed
• Safe for Kids & Pets
• Improves Soil Health
• Non-Burning, Water-Soluble Formula

❌ CONS ❌

• Contains Animal Manure – Not for Vegan Gardeners

9. Miracle-Gro Shake ‘N Feed Tomato, Fruit & Vegetable Plant Food

A lot of gardeners stay away from Miracle Gro because they contain some questionable ingredients if you practice organic gardening. However, their Shake ‘n Feed formula contains micronutrients and ingredients that feed the microbes in the soil along with extra calcium that plants need.

This fertilizer is heavier on the nitrogen and potassium with a 10-5-15 NPK ratio. So, this is ideal for using at the start of the growing season, especially if you didn’t add compost to your soil.

Some of the ingredients include:

• Feather Meal
• Kelp Meal
• Alfalfa Meal
• Earthworm Castings
• Urea Ammonium Phosphate
• Copper Oxide
• Iron Oxide
• Zinc Oxide
• Bone Meal

And so much more!

I wouldn’t suggest adding fertilizer with this amount of nitrogen after flowers develop since nitrogen encourages plants to develop greens rather than fruits. However, it can help poor soil turn into healthy soil!

Miracle Gro only recommends reapplying this fertilizer every three to four months. So, depending on the length of your growing season, you might only apply this before planting.

✅ PROS ✅

• Great for Poor Soil
• Contains High Nitrogen & Potassium
• Extra Calcium
• Safe Around Kids & Pets
• Slow Release
• Won’t Burn Plants

❌ CONS ❌

• Not for Regular Applications
• Slightly Pricey

10. Greenway Biotech Cucumber Fertilizer

Most fertilizers are not designed for one plant, but the Greenway Biotech’s Cucumber Fertilizer is specifically designed for growing cucumbers. It is premixed with the proper balance of nutrients your cucumber plants need.

Greenway is a completely water-soluble fertilizer, and a single pound of this fertilizer creates 200 gallons of fertilizer. A little goes a long way, so a bag will last you quite awhile.

The NPK ratio is 8-16-36 with all the minerals your soil and plants need to thrive at all stages. Plants also receive:

• Boron
• Copper
• Iron
• Manganese
• Zinc

It’s great for in-grounds, but you also can use this for hydroponics or container gardens.

✅ PROS ✅

• Easy to Apply
• Specifically Designed for Cucumbers
• Hydroponics & Container Garden Safe
• Contains Multiple Minerals for Growth
• Lasts a Long Time!

❌ CONS ❌

• Pricey
• Doesn’t Contain Calcium or Magnesium

How Often to Fertilize Cucumbers

How often to fertilize cucumber plants depends on the type of fertilizer you pick. Make sure to read the back of the container before using.

Some slow release fertilizers recommend feeding every month or every two months. Water-soluble fertilizers may suggest weekly applications, especially for cucumbers grown in pots. When you fertilize anything in containers, you will need to feed them more because the nutrients wash out faster.

When to Fertilize Cucumbers

Start by adding fertilizer or nutrients to the soil before planting your cucumber seeds or cucumber seedlings. This is easy to do by either adding compost to the soil or fertilizer in the bottom of the planting hole.

Once flowers appear on the cucumber plants, fertilize again, but if the brand suggests fertilizing more frequently, it’s safe to do so during the growth period.

Watch for signs of over fertilization like plant failure or yellowing cucumber leaves. This may mean you are fertilizing too often.

In general, biweekly or monthly fertilization is safe.

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Growing a huge yield of cucumbers is easy, but you have to fertilize. Don’t make the same mistakes I made and think fertilizing isn’t needed – it really is! Grab the best fertilizer for cucumbers to get optimal results.