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Top 5 Best Fertilizers For Cucumbers (2023 Review)

By: Heather

best fertilizer for cucumbers

At the moment I have a healthy young cucumber plant spreading its third true leaf.

It’s high spring here and this seedling has been growing since April. Come the last frost date, this guy’s going in the ground. 

You’d be surprised how big it’ll grow with the proper care, even in my clay-ey earth (more on soil type later).

One vine will yield pounds of cukes. They’re one of the most forgiving vegetables!

However I will say that my personal favorite fertilizer (Miracle-Go Organics) makes a HUGE difference and helps me achieve my dream of cucumber-and-cheese sandwiches by mid-summer. 

I’ll explain to you in detail why below, but if you’re short on time and curious about the best fertilizers for cucumbers, look no further than the table below

Miracle-Gro Performance Organics All Purpose Plant Nutrition Granules
  • Balanced nutrient ratios
  • Organic ingredients
  • Affordable
  • Balanced nutrient ratios
  • Organic ingredients
  • Affordable
View on Amazon
Jobe's Organics Vegetable & Tomato Fertilizer Spikes
  • All natural, environmentally friendly
  • Continuous release formula
  • Low odor
  • All natural, environmentally friendly
  • Continuous release formula
  • Low odor
View on Amazon
Osmocote Plus Outdoor and Indoor Smart-Release Plant Food
  • 100% organic natural ingredients
  • Controlled-release granules
  • Micronutrients for healthy cucumber growth
  • 100% organic natural ingredients
  • Controlled-release granules
  • Micronutrients for healthy cucumber growth
View on Amazon
Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer
  • Packed with soil microbes and beneficial fungi
  • Contains no GMOs, chicken manure or sewage sludge
  • Feeds for several months
  • Packed with soil microbes and beneficial fungi
  • Contains no GMOs, chicken manure or sewage sludge
  • Feeds for several months
View on Amazon
Greenway Biotech Cucumber Vegetables Fertilizer
  • 8-16-36 plus trace minerals and micronutrients
  • Environmentally friendly
  • water soluble
  • 8-16-36 plus trace minerals and micronutrients
  • Environmentally friendly
  • water soluble
View on Amazon

My Overall Top #1 Pick: Miracle-Gro Performance Organics All Purpose Plant Nutrition Granules

I chose Miracle-Gro Performance Organics All Purpose Plant Nutrition Granules as the best fertilizer for cucumbers for several reasons. 

For one thing, it’s the easiest to access. It has a low price-point and ready availability: I can find Miracle-Gro products at Walmart, my local general store, even the hardware store. 

For another, a one-pound supply will last you a long time. I’m almost embarrassed to say how long I’ve been using this one-pound box, and I use it for both houseplants and vegetables. It really is a useful product. 

Miracle-Gro Performance Organics stands out as the best fertilizer for cucumbers, specifically. Cucumbers need a steady supply of nutrients throughout the growing season, and this fertilizer delivers just that. 

What sets this fertilizer apart is its balanced nutrient ratios that ensure cucumbers receive the perfect blend of nitrogen, phosphorus, and potassium, all crucial for vigorous development. 

One of the key aspects of growing cucumbers successfully is promoting robust vine growth. Many times home gardeners see weak vines that can’t provide proper nutrient and moisture flow to cucumber flowers and fruits. It’s similar to problems gardeners have with pumpkins.

With Miracle-Gro Performance Organics granules, I have seen great results in this specific growing condition. Cucumber vines become robust, climbing and spreading easily, maximizing their exposure to sunlight and airflow. 

This leads to healthier foliage and more efficient exposure to sunlight, which directly translates into higher yields. 

Moreover, this fertilizer plays a vital role in one of the cornerstones of cucumber growing: disease resistance. 

Cucumbers are susceptible to various pests and diseases, including squash beetles and downy mildew. With the consistent use of this fertilizer, I noticed an increased resilience in my cucumber plants against these common problems. 

The organic ingredients in the granules fortify cucumber plants’ natural defenses, making them less vulnerable to cucumber ailments.

When it comes to fruit production, Miracle-Gro Performance Organics fertilizer truly shines. Cucumbers require an abundance of nutrients to set and ripen fruits. 

This is a balanced fertilizer that ensures cucumbers receive the right nutrients when they need them. As a result, I get cucumbers that are firm, crisp, juicy, and uniformly green.

In addition to its particular benefits for cucumbers, Miracle-Gro Performance Organics contributes to overall soil health, so your plot will be better off no matter what you grow in it next season. 

Organic ingredients improve soil structure, promoting better water retention and nutrient absorption.

In conclusion, Miracle-Gro Performance Organics’ organic composition, balanced nutrient formula, and convenience make it the #1 best fertilizer for cucumbers. I have seen robust vine growth, disease resistance, and fruit production.

Check out this nifty time-lapse of a cucumber from seed to harvest. It shows that you can grow a cuke using very little soil space, but I bet this guy used fertilizer! 

Top 5 Best Fertilizers For Cucumbers

In a hurry? No worries! Below are my top 5 fertilizers for your cucumbers!

  1. Miracle-Gro Performance Organics All Purpose Plant Nutrition Granules (Best Overall Growing Formula)
  2. Jobe’s Organics Vegetable & Tomato Fertilizer Spikes (Best for Mature Plants)
  3. Osmocote Plus Outdoor and Indoor Smart-Release Plant Food (Best for One Application)
  4. Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer (Best for Starting Cucumbers)
  5. Greenway Biotech Cucumber Vegetables Fertilizer  (Best Remedy for Problems)

Why Should You Invest In A High-Quality Fertilizer For Your Cucumbers?

As with any plant, fertilization plays a vital role in providing cucumbers the nutrients they need for overall health and high yields. 

Nutrient composition in cucumber fertilizer

Although not as picky about growing conditions as some vegetables, growing an optimum cucumber crop demands high nutrients, especially for your three pillars of nitrogen, phosphorus, and potassium (NPK). 

While you could buy each of these nutrients separately and hand-concoct a cucumber mix, a well-rounded vegetable fertilizer does the work for you, giving you great cukes with that foundational root system, strong vines, and abundant foliage to catch the sun. 

Each of these is essential to supporting robust cucumbers! I can’t tell you how frustrating it is to lose a plant you’ve nurtured 3 months from seed because the vines are too weak to support fruit, or the foliage is sparse and not getting that necessary sun energy.

Nutrient levels supplied by a high-quality fertilizer will contribute to better fruit set, quality, and yield.

Soil structure and organics

There’s a lot going on with cucumber growth that we don’t ever see. Fertilizers help replenish soil below the surface with nutrients that may be depleted from previous crops or leaching. 

When in doubt, test your soil to determine the specific nutrient requirements of the soil, enabling targeted fertilizer application.

Organic fertilizers, in particular, provide slow-release nutrients, improve soil structure, and enhance the overall health of the soil ecosystem. 

Certifying organizations like OMRI emphasize the importance of choosing organic fertilizers that meet specific quality standards, ensuring your garden is more sustainable and environmentally friendly.

Like I said at the get-go, cucumbers aren’t the fussiest vegetables, but they do take months to grow and can fall prey to diseases, pests, and nutrient deficiencies.

Why spend months growing something that doesn’t fruit, or yields much less or later than you’d planned on? A good fertilizer will supply essential elements cucumbers need and the optimum yields you crave. 

What to Consider when Choosing the Right Fertilizer for Cucumbers?

Like easy-care succulents, you can toss a cucumber seedling into any dirt and watch it grow – somewhat. If you want to capitalize on your time and efforts, though, you need to know a little bit about what specific soil nutrient requirements cucumbers need for optimal growth and productivity. 

The operative word here is optimal!

Soil Composition and Watering

No surprise: Cucumbers love rich, well-draining soil that’s fertile and moisture-retentive. You knew that; all plants love that. We need to drill down a bit to get to the specifics for cucumbers. 

Cucumbers actually like slightly acidic to neutral pH levels in a fairly tight range from 6.0 to 7.0. You might consider giving your cukes a dose of used coffee grounds now and then.

It’s also really important to keep your soil evenly watered for cucumber plants: Never too much water, never too little. A good rule of thumb is to water thoroughly (but not enough to form a puddle) every three days it doesn’t rain, potentially more in very hot conditions.

It can help to look for a fertilizer with a recommended application of once-a-week, when you’ll probably be watering, anyway. Make this fertilizer a part of your regular garden maintenance and you’ll never skip a dose inadvertently.

Macro- and Micronutrients

In terms of soil nutrients, cucumbers are pretty easy customers: All they want is balanced nutrient love, nothing too excessive. 

Specifically, try to keep your macronutrients and your micronutrients in line, nothing overly abundant. 

Primarily, of course, cucumbers need nitrogen (N), phosphorus (P), and potassium (K). 

Nitrogen is essential for promoting vegetative growth, phosphorus for root development and fruiting, and potassium aids in overall plant vigor and disease resistance.

Additionally, as far as micronutrients go, focus on providing cucumbers calcium (Ca), magnesium (Mg), and boron (B). 

Calcium is crucial for preventing blossom end rot, a common disorder in cucumbers, while magnesium contributes to chlorophyll production and enzyme activation. Boron plays a vital role in flower pollination and fruit development.

Soil Type

Regarding soil type, cucumbers are no different than any veg: they thrive in loose, well-drained soil with good aeration. They are particularly suited to sandy loam or loamy soil types. These provide a balance between water retention and drainage, which is so key for cucumbers. 

Sandy soil types facilitate good root development and don’t get waterlogged, while loamy soils offer optimal nutrient availability and moisture retention.

Nutrients for Cucumbers at Different Stages

Young cucumbers just establishing roots and foliage need higher nitrogen levels. As the plants begin to flower and fruit, phosphorus and potassium become more important. This is also when your micronutrient calcium comes into play for preventing blossom end rot.

It’s also key to water consistently but not overly, while avoiding getting leaves wet (which can invite downy mildew and sunburn).

Liquid vs. Granular Fertilizer

Now a note on types of fertilizer. From personal experience, I like liquid fertilizers because they seem to dilute more readily, just from eyeballing the watering can. It seems to me this would promote more even nutrient dosage. 

That said, I more often use granular fertilizer because it’s simply more common and readily available, and it’s probably more bang for your buck. 

Buy Organic When Possible

You might have guessed I’m not a picky gardener, but I do try to go organic when possible, and when it doesn’t demand too much from my wallet. This is simply because I like the idea of putting things back into the earth that came from the earth without a lot of pesticides or other additives. 

How to Fertilize to Promote Cucumbers

It’s generally best to apply fertilizers to the soil rather than spraying the leaves of cucumbers. This is because cucumber plants primarily absorb nutrients through their roots. Watering the soil with fertilizers allows the nutrients to reach the roots most efficiently. 

Spraying the leaves with fertilizers is generally not recommended, since fertilizer can actually burn foliage. Also, wetting cucumber leaves can invite diseases – it’s these big-leaved cucurbits that fall prey to ailments like downy mildew. 

How Often to Fertilize Cucumbers

You’ve seen here that fertilizers range in recommended application from once a week to once a growing season. It depends, in the first place, on what kind of fertilizer you’re working with. Time-release granules will essentially dose themselves, whereas other types of fertilizer let you decide when it’s time.

As a general guideline, fertilize cucumbers every 2-3 weeks during the growing season. That said, it’s crucial to monitor the plants and adjust the frequency based on their growth and nutrient requirements. 

My own cucumbers have some spotting on the leaves that I suspect might be due to a lack of nitrogen, so I started fertilizing them very early in their growth, before they’re even really vining. 

That said, guard against fertilizing too much, which can lead to excessive leaf and vine growth with fewer fruits.

When to Fertilize Cucumbers

It’s a good idea to start fertilizing cucumbers when they have established a few true leaves. This is typically about 3-4 weeks after starting seedlings. Fertilizing at this stage provides a nutrient boost to support healthy development.

It’s also beneficial to provide additional phosphorus and potassium when the plants start producing flowers. These nutrients support flower formation and fruit development. You can use a fertilizer with a higher middle number (phosphorus) in the NPK ratio during this stage.

Signs that Fertilization is Needed in Cucumbers

Signs that indicate the need for fertilization in cucumbers can vary. Yellowing leaves may indicate nutrient deficiencies, particularly nitrogen. However, it’s essential to note that yellowing leaves can also be caused by other factors such as pests, diseases, or overwatering. 

Personally, fertilizing with a well-rounded fertilizer is one of my first lines of defense when I notice any issues with my vegetable plants. I figure a nice dose of vitamins can’t hurt while I suss out potential additional issues with the growing conditions.

More clear-cut are cases of undernourishment at later stages of cucumber growth. These cucumber plants will show stunted growth, reduced fruiting, or the fruits might be particularly small. In that case, try our pick for Best Remedy.

Application Tips

Focus on applying fertilizers to the soil around the base of cucumbers rather than spraying the leaves. 

Fertilize every 2-3 weeks during the growing season, adjusting based on plant growth. 

Start fertilizing when the plants have established a few true leaves, and consider providing additional phosphorus and potassium when they start flowering. 

Signs of nutrient deficiencies include yellowing leaves, stunted growth, and poor fruit development. 

Mixing fertilizers with water before application is generally recommended for proper nutrient distribution. 

Follow these guidelines, and before you know it you’ll be on your way to maxing out your cucumber harvest!

My Reviews of the Best Fertilizers for Cucumbers

1. Miracle-Gro Performance Organics All Purpose Plant Nutrition Granules (My Top Pick)

The old stand-by in new organic form proves particularly effective in promoting growth and production in fruiting plants like cucumbers.

All-natural ingredients are both plant and animal based and offer a balanced ratio of N-P-K for green foliage, robust vining, and juicy cukes.

PROS (+) CONS (-)
+ Micronutrient blend for high performance
+ 1 pound typically lasts years, so it’s a bargain buy
+ Targets foliage, flower, and fruit health
– Recommends repeat feedings
every 7 days

2. Jobe’s Organics Vegetable & Tomato Fertilizer Spikes (Best for Mature Plants)

This 2-7-4 blend from animal and plant ingredients will encourage your cucumbers to flower and fruit healthily.

The spikes that are inserted directly into the soil for continuous release are a convenient alternative to conventional fertilizers.

Cucumbers will show better resilience against diseases and pests and better fruiting. High phosphorus content specifically targets root growth. 

PROS (+)CONS (-)
 + No mixing, continuously feeds
to the roots for up to 8 weeks
+ Another organic choice
+ 2-7-4 ratio to promote flowering and fruiting
– Requires multiple spikes per plant. You’ll likely need a couple boxes for one season.
– Watch for over-application of phosphorous, which causes yellowing leaves.

3.  Osmocote Plus Outdoor and Indoor Smart-Release Plant Food (Best for One Application)

This is a frequent recommendation by nursery growers, which should tell you something.

Cucumber gardeners have found its powerful formula helpful.

Controlled-release granules provide plants a steady supply of nutrients regardless of watering/rain conditions.

Micronutrients contribute to healthy cucumber growth.

PROS (+) CONS (-)
+ Gentle formula never burns plants.
+ 15-9-12 NPK ratio often recommended by nurseries for beautiful growth.
+ Use every 6 months, or only one application for cucumbers.
– Contains molybdenum, which makes plants toxic for grazing animals.
– Only one feeding for cucumbers means you can’t readily control or adjust nutrients as needed.

4. Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer (Best for Starting Cucumbers)

This might seem like a bargain-basement item, but it gets rave reviews.

Packed with soil microbes and mycorrhizae, beneficial fungi that form symbiotic relationships with root structures, this formula is tailored to feed your plants at its roots essential for strong growth.

PROS (+)CONS (-)
+ Good for both new and established cucumber plants.
+ Must only apply every other month.
+ Filled with root micronutrients.
– Some people object to the smell.

5. Greenway Biotech Cucumber Vegetables Fertilizer  (Best Remedy for Problems)

This is the choice for growers with in-ground or hydroponic gardens, a targeted formula that will produce lush vining, foliage, and healthy cucumbers.

Users have found it can rescue plants under distress.

Be careful with application, however – without instructions on the label, it’s difficult for beginners to gauge dosage.

PROS (+)CONS (-)
+ 8-16-36 formula that can be used in the soil or for hydroponic cucumbers.
+ Quickly and efficiently dissolves in water.
+ Can remedy certain nutrient deficiencies.
– Watch for potassium poisoning, which will yellow cucumber leaves.
– Pricey. 
– No instructions for application.

My Top Pick: Miracle-Gro Performance Organics All Purpose Plant Nutrition Granules

Miracle-Gro Performance Organics All Purpose Plant Nutrition Granules is my top pick because it’s well-rounded, easy to use, and gives you complete control over dosage. 

Cukes need a little boost mid-season? Top ‘em up with this fertilizer. Cukes flourishing during frequent rains and sunny spells? Go ahead and skip a weekly feeding. 

As someone who likes to keep close track of her vegetables at all stages (the fun is in the process), Miracle-Gro Performance Organics All Purpose Plant Nutrition Granules offer me that flexibility in usage.

With this top pick, I won’t worry if I’m overdoing it on potassium, which can lead to leaf damage, or underdoing it undetected until my cucumbers ripen tiny and soft because they’ve fallen prey to a disease.

It’s also convenient that these granules are recommended to be watered-in once a week. Once a week might be all you need to hand-water, if the rains are right. Remember, cucumbers detest overwatering! 

Final Thoughts on the Best Fertilizer for Cucumbers

Cucumbers are a joy to grow. They don’t demand a lot, for the amount they give back. They’ll tolerate quite a bit of neglect, but with just a little extra effort, you’ll have some strong vines supported on a simple trellis, popping out firm, juicy fruits like nature intended.

Speaking of a trellis, with cucumbers I like to angle my support structure at 30-45 degrees to the ground so I’m not constantly fighting gravity. A freebie pallet propped on a couple stakes might do it. 

I love making garden structures with bamboo, and most cucumber varieties are lightweight enough that you can construct a nice, leaning support with just slim bamboo.

As for fasteners, torn fabric is gentle and won’t damage vines. For a tidier look, buy a big roll of twist ties – mine have lasted me years! And you know I like that thrift!

Keep gardening up!

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