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The Best Fertilizer For Cucumbers

Cucumbers grow easily when they get enough sun, water, and nutrients.

So, to make sure your plants stay healthy and to maximize fruit yield it’s a good idea to use a fertilizer.

Our recommended choice is Lilly Miller Morcrop Tomato & Vegetable Food.

This fertilizer has the right balance of essential nutrients for successful growth. And continues to feed your plants for up to 6 weeks at a time.

The best fertilizer for cucumbers at a glance:

All links lead to Amazon, where you can find more information & customer reviews.

The Best Fertilizer For Cucumbers

Lilly Miller Morcrop Tomato & Vegetable Food

Lilly Miller Morcrop

This fertilizer provides a 5-10-10 NPK formula that works well for cucumber plants. And you can also use it for any other vegetables you’re growing in your garden.

Cucumbers use twice as much potassium (K) than nitrogen (N) as they grow. So this product gives you a great balance.

The nitrogen is provided as both slow and quick release. So you get fast nutrition to your plants and quick growth. But you also get the slow release of nutrients that continues to feed them for up to 6 weeks at a time.

It’s also fortified with 4% calcium. This prevents your cucumbers from developing blossom end rot, a disorder caused by calcium deficiency that spoils the fruit.

The product comes as granules that you mix into the soil surface and then water. Use it when you first plant your cucumbers and then every 4-6 weeks while they’re growing.

Customers report impressive yields. With the only drawback being the smell of manure when it’s first applied.

  • A good NPK ratio for cucumber plant growth and fruit yield
  • Fortified with calcium to prevent blossom end rot
  • It contains fast-release and slow-release nitrogen
  • Unpleasant odor when first applied

Espoma Garden Tone


This natural fertilizer is ideal for growing cucumbers if you prefer organic gardening.

It provides everything your plants need to grow and bear fruit. With an NPK ratio of 3-4-4. And a full range of essential secondary nutrients and micronutrients. Making sure that your plants won’t suffer from any nutrient deficiencies in the soil.

While the NPK ratio of organic fertilizer is always lower than products containing synthetic fertilizer, it does have other benefits that encourage strong growth.

To start with, it’s great for producing healthy long term soil for your plants to grow in. Improving texture, structure, and aeration.

And the organic material is broken down slowly, providing continuous nutrition over many weeks.

Espoma Garden Tone also contains beneficial soil microbes that increase nutrient availability.

And it’s safe for the environment, with no worries about phosphorus runoff.

  • Natural & organic
  • Contains all the essential nutrients your plants need
  • Added soil microbes improve the soil health and increase nutrient availability for root uptake
  • Safe for the environment
  • Strong odor
  • Lower NPK than synthetic fertilizers

Dr. Earth Home Grown Tomato, Vegetable & Herb Fertilizer

Dr. Earth

Dr. Earth’s 100% natural and organic fertilizer has a 4-6-3 NPK ratio, with additional nutrient benefits derived from its organic composition.

As the organic material breaks down, it releases essential minerals, carbohydrates, proteins, humic acid, and trace elements that enrich your soil, fostering optimal cucumber plant growth.

What I really like about this fertilizer is its inclusion of eight diverse strains of ecto- and endo-mycorrhizae, which in my experience, really make a difference to results.

These beneficial fungi form a symbiotic relationship with the roots of your plants, extending into the soil to enhance nutrient uptake, water absorption, and oxygen availability. The result is healthy and robust growth, increased fruit yield, and improved resilience to drought conditions.

Furthermore, the 7.5% calcium in this fertilizer offers protection against the dreaded blossom end rot, safeguarding your plants and ensuring their continued vitality.

One of the notable advantages of using this fertilizer is its user-friendly nature. You can apply it without concerns about overuse or potential plant damage because it does not cause nutrient burn.

This product consists of premium fish meals and nutrient-rich kelp, but the fertilizer distinguishes itself by its lack of unpleasant odors often associated with organic fertilizers. Instead, it exudes a raw, earthy scent, that is far more pleasant to smell.

Customers have reported impressive results, with their cucumbers experiencing rapid growth and high yield.

In addition to its outstanding performance, this fertilizer boasts an impressive array of organic credentials, including certifications from reputable organizations such as the National Organic Program (NOP), Organic Material Review Institute (OMRI), California Certified Organic Farmers (CCOF), and Organic Input Materials (OIM).

Moreover, it proudly carries the verification of being Non-GMO Project verified, assuring you of its integrity and adherence to organic principles.

Available in a convenient 4 lb bag, you can also purchase this fertilizer in various other sizes to suit your specific needs, ranging from 25 lbs, 12 lbs, and 2 lbs, down to a compact 1 lb bag.

  • Long list of organic credentials
  • Ecto and endo-mycorrhizae
  • Calcium to prevent BER
  • A lower amount of NPK than synthetic fertilizers

Neptune’s Harvest Tomato & Veg Fertilizer

Neptune's Harvest

Neptune’s Harvest consists of sustainably harvested North Atlantic fish, seaweed, molasses, humic acids, and yucca extract. This unique blend offers many benefits for your plants.

The fertilizer comes as a liquid and works quickly, with my plants showing noticeable improvement somewhere from twenty-four to forty-eight hours after application. I have observed good results with my cucumbers, which grow robust and healthy, making them more likely to withstand stress and fend off diseases.

For my seedlings, a ½ ounce of Neptune’s Harvest Tomato & Veg Fertilizer 2-4-2 in a gallon of water every two weeks yields exceptional results. This carefully measured dosage provides the necessary nutrients for their early growth stages.

For my cucumber plants in the ground, I have found that utilizing one ounce of this fertilizer per gallon of water every two weeks is ideal for maintaining optimal health and vigor. This regimen ensures they receive the appropriate nourishment for continuous growth and high yield.

To prevent any wastage or unpleasant odors, I mix only the amount of Neptune’s Harvest that I immediately require. Although this fertilizer may be slightly higher priced and lacks official organic certification, its effectiveness makes it a good choice for organic gardening.

  • Organic
  • Provides a wide range of nutrients
  • Liquid fertilizer — available for quick uptake
  • Lacks organic certification
  • Smells a bit for a couple of days after application

EB Stone Organic Tomato and Vegetable Food

EB Stone

EB Stone’s organic vegetable food has a balanced 4-5-3 NPK ratio, carefully crafted from a blend of natural ingredients.

This effective formulation includes feather meal, bone meal, blood meal, bat guano, and dried chicken manure, all working synergistically to provide optimal nutrition for your cucumber plants.

This fertilizer contains a significant 3% calcium content to address the common problem of blossom end rot (BER). This addition helps prevent BER and corrects soil acidity, ensuring the healthy development of your cucumbers.

This fertilizer improves soil health by incorporating beneficial microbes. These mycorrhizal fungi strengthen the plants by facilitating enhanced nutrient uptake, leading to robust growth and abundant fruit production.

The versatility of this fertilizer extends beyond cucumbers, making it an excellent choice for nourishing other vegetables in your garden.

One consideration to note is that similar to other organic fertilizers utilizing animal-derived meal and manure, this product does have an unpleasant odor. However, if the smell does not bother you, it remains an excellent choice for organic gardening enthusiasts seeking effective and natural solutions.

It comes packaged conveniently in a 4 lbs container, providing ample supply to meet your gardening needs.

  • Organic fertilizer
  • Prevents BER
  • Corrects soil acidity
  • Unpleasant smell

Down to Earth Organic Vegetable Garden Fertilizer

Down To earth

Down To Earth is a balanced natural fertilizer with a 4-4-4 NPK ratio. It’s OMRI listed for organic use, making it a good choice for organic gardeners.

It has all the benefits you’d expect from organic fertilizer. It’s slowly broken down by microbes in the soil. Gradually releasing nutrients for your plant to use, without the risk of overdoing it and causing fertilizer burn.

And the soil it helps you build over time is healthy. With a high level of microbe activity, and great supporting structure for your plants.

Like most organic fertilizer it does have a strong odor when first applied. But it goes away after a few days.

  • All-natural and organic
  • OMRI listed
  • Creates healthy soil with good microbe activity
  • Environmentally friendly
  • Strong smell
  • Lower NPK than chemical fertilizers

Jobe’s Organics Fertilizer Spikes For Vegetables

Jobe's Organics

In my experience, Jobe’s Organics Fertilizer Spikes for Vegetables are a good choice for growing cucumbers in containers.

They’re convenient to use, you place the spikes in the container once, and their slow-release formula ensures continuous nourishment for your cucumber plant for up to six weeks, eliminating the need for regular liquid fertilizer applications, and simplifying your gardening routine.

Another great thing about them is that the spikes have little odor, making them pleasant to use.

Being organic is a preference for many people, and Jobe’s Organics Fertilizer Spikes align perfectly with a natural approach to growing cucumbers.

The 2-7-4 NPK ratio of these spikes is well-suited for the entire growing season of cucumber vines without concerns about excessive foliage growth.

This balanced ratio ensures steady and controlled growth without compromising fruit production. And the spikes’ high phosphorus content facilitates abundant blooms and a bountiful cucumber harvest.

It’s worth noting that Jobe’s Organics Fertilizer Spikes, although highly effective for container-grown cucumbers, may not be suitable for large garden plots due to the potentially high quantity required, which could be impractical and uneconomical.

  • Good for growing in containers
  • Slow release of nutrients
  • Natural and organic
  • Less economical for large garden plots than some other options

Osmocote Smart-Release Plant Food Flower & Vegetable


Osmocote flower & vegetable food has a nutrient-rich 14-14-14 NPK formula.

It comes in slow-release granules that have a special semi-permeable resin coating. When they get wet the nutrients inside dissolve, enabling their release at a gradual rate. Feeding your plants for up to 4 months with each application.

Customers are happy with the growth of their plants when using this fertilizer. But some people don’t like the way the resin balls accumulate in the soil without dissolving.

  • High nutrient content
  • Feeds plants for 4 months
  • The empty shells don’t dissolve and are left in your soil after they release their nutrients

Greenway Biotech Cucumber Fertilizer


Many fertilizers are designed for use on all vegetables, but not many are specifically formulated for use on cucumber plants.

This fertilizer has an ideal mix of nutrients for cucumbers, with an NPK of 8-16-36 and secondary nutrients such as boron, iron, zinc, copper, and manganese.

The fertilizer is water-soluble and goes a long way, with a single pound making up to 200 gallons of fertilizer. You can use it in your garden beds, containers, or with hydroponics.

  • Cucumber specific nutrient mix
  • A little goes a long way
  • High NPK
  • Surprisingly, no calcium in the mix

Miracle-Gro Water Soluble Plant Food Vegetables & Herbs

Miracle Gro

Miracle-Gro is a well-known brand with a successful line of fertilizers. This one is designed for gardening vegetables and herbs.

It’s an 18-18-21 NPK fertilizer that provides quickly available nutrients for everything in your vegetable garden. As well as cucumbers, use it on your tomatoes, carrots, peppers, squash, zucchini, and all Cucurbita, to keep them in good health while they grow and maximize their yield.

It’s easy to use. Just mix it together with water in your watering can each time you water your plants.

And as it’s easily water-soluble, it’s a good choice if you’re growing hydroponic cucumbers.

  • High NPK
  • Water soluble—useful if you grow cucumbers using hydroponics
  • It can cause nutrient burn if you don’t follow the instructions carefully

Cucumber Nutrient Requirements

cucumbers growing in the sun

Cucumbers need plenty of the primary nutrients — nitrogen, phosphorus, and potassium — to grow. So it’s a good idea to get an NPK (Nitrogen-Phosphorus-Potassium) fertilizer that provides all 3.

In particular, they’re hungry for potassium, and require more of it than the other 2. NPK fertilizer with a ratio of 5-5-10, or 5-10-10 is a good choice to cater to a cucumber plant’s growing requirements. But you can also use a balanced fertilizer such as 10-10-10.

They also need secondary nutrients and micronutrients that are usually present in the soil.

A common nutrient deficiency is a lack of magnesium. This sometimes occurs mid-season and reduces fruit yield. The symptoms include the leaves turning yellow, which is first noticeable on the older, lower leaves.

But adding Epsom salt as a side dressing can correct the problem.

What Type Of Fertilizer To Use On Cucumber Plants

The best fertilizer for cucumbers comes in 2 different types: organic and synthetic (chemical). They each have their own advantages.

Organic fertilizer often contains the full range of primary and secondary nutrients your cucumbers need for healthy growth. As well as many essential micronutrients.

It breaks down in the soil slowly, releasing nutrients throughout the growing season (you can also get liquid natural fertilizer that provides faster access to nutrients).

Adding organic matter also helps to build healthy soil for the long term. With good texture, drainage, and aeration.

Synthetic fertilizer has the advantage that it’s usually higher in NPK. But it usually doesn’t have the full range of nutrients that are provided by organic fertilizers.

It comes as a water-soluble powder that provides a fast release of nutrients to the soil for plant uptake. This leads to rapid growth. But also the need to fertilize frequently as the nutrients are lost from the soil quicker.

You can also get it in slow-release fertilizer granules that break down and release the nutrients over a period of weeks.

Well-Aged Compost For Cucumbers

Another good option for fertilizing your cucumber plants is compost. As it’s organic, it has all the benefits mentioned above.

For best results, try to work it into your soil before you plant your cucumbers.

Making your own compost is easy, and involves combining soft green materials (vegetable waste, grass clippings, etc) with woody material (wood chippings, prunings, dead leaves, and straw) in a compost bin and allowing them to decompose together.

You can also buy bags of compost at some garden centers.

Growing Conditions For Cucumbers

Cucumbers are easy to grow. But the best cucumber fertilizer isn’t the only thing they need. Here are some tips to help you get the most out of your plants and produce the best cucumbers.

  • When planting cucumbers put them in a location where they can get 6 or more hours of direct sun each day
  • They need a lot of water to grow and do well in fast-draining soils
  • Soggy soil makes it hard for them to uptake oxygen and fungal infections may develop on their roots
  • 1 or 2 deep waterings a week is ideal, wait until the top inch of soil is dry first
  • If you’re growing in containers or pots, make sure they have good drainage holes that allow water to easily run out
  • They like warm conditions and will struggle to grow at temperatures below 60°F with seeds failing to germinate
  • At temperatures below 50°F the leaves start to turn brown and die—so be careful not to plant them outside until nighttime temperatures are sufficient
  • They prefer a soil pH of around 6.8, but they can go a bit higher
  • If you start them inside remember to harden them off for a couple of weeks before permanently moving them into your garden — you can also move them into a greenhouse first

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