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It’s a favorite summer pastime for many—grab a salt shaker, pick a ripe cucumber, and eat it right there in the backyard. Cucumbers, members of the cucurbit family, grow quickly and receive ample nutrition in warm sunny conditions when the days are long.
While some gardeners have honed their soil over the years to provide optimal conditions for growing cucumbers and other produce, most plants will still benefit from added nutrients. When looking for a fertilizer for cucumbers, knowing a few cucumber-growing basics is helpful.
Although cucumbers are actually a fruit, they’re grown as a vegetable, and they benefit from the same type of fertilizer used to feed tomatoes, peppers, and other garden vegetables. Ahead, learn what to look for when shopping for the best plant food for cucumbers, and find out why the following products are among the best fertilizer for cucumbers.
- BEST OVERALL: Miracle-Gro 2000422 Plant Food
- BEST BANG FOR THE BUCK: Jobe’s 09026NA Plant Food Vegetables & Tomato
- BEST ORGANIC: Dr. Earth Organic 5 Tomato & Herb Fertilizer
- BEST WATER-SOLUBLE: Miracle-Gro Water Soluble Plant Food
- BEST FOR CONTAINERS: Jobe’s 06028 Fertilizer Spikes Vegetable and Tomato
- BEST STARTER FOOD: Down to Earth Organic Vegetable Garden Fertilizer
- MOST COMPLETE: Espoma GT4 4-Pound Garden-Tone 3-4-4 Plant Food
- ALSO CONSIDER: Element Nutrients Flower Fuel The Best Bloom Booster
What to Consider When Choosing the Best Fertilizer for Cucumbers
Cucumbers are considered among the easiest food-producing plants to grow. Gardeners can choose from nearly 100 varieties of cucumbers and can select plants based on taste, growth habit, and productivity. While some cucumber plants send out long vines that can be trained on tall trellises, others are compact and can be grown in patio containers. However, cucumbers do not grow well in most indoor growing conditions since they need long sunny days to produce fruit.
Even the best cucumber fertilizer is not a replacement for a bright, sunny location and healthy soil, but adding a good fertilizer can be a factor in growing strong plants that produce abundant tasty cucumbers.
Types of Fertilizer for Cucumbers
Few fertilizer products, including those considered to be the best fertilizer for cucumber plants, are specifically labeled as being “cucumber fertilizers.” Instead, most are labeled as all-purpose vegetable fertilizers (or tomato fertilizers). Fertilizers that work well for cucumbers are available in one of four types, some of which are better suited to specific growing conditions than others.
- Granular: This type of fertilizer resembles tiny pellets and gradually releases nutrients to keep plants fed for several weeks. The granules are mixed within the top inch or two of soil, where they slowly dissolve.
- Liquid: Available in concentrated form for mixing with water or as ready-to-spray foliar plant food, liquid fertilizers are rapidly absorbed by the plant, but they also wash out of the soil rather quickly, so more frequent feedings (every week or so) may be needed.
- Spikes: Another time-release fertilizer, spikes contain dry nutrients that have been pressed into hard cylinders growers push beneath the soil’s surface, where they will gradually dissolve and release nutrients. Spikes are arguably the best fertilizer for cucumbers in containers because they provide continuous nutrients in limited amounts of soil.
- Water–soluble: This type of fertilizer comes in a fine granule or powdered form and is designed to dissolve quickly in water. Gardeners can stir it into the water in a watering can or fill a garden hose dispenser and spray a large area of plants.
Nutrient Requirements
The confusion over what the NPK numbers listed on fertilizers mean can be easily solved by learning what the numbers stand for. The product’s NPK analysis stands for the amount of nitrogen (N), phosphorus (P), and potassium (K) the product contains by weight.
Cucumbers have similar growing needs to most other garden vegetables, and they prefer a fertilizer with less nitrogen than phosphorus or potassium (often called potash by gardeners). For example, NPK ratios of 5-8-10 and 3-3-3 would be suitable for growing cucumbers because the nitrogen content does not exceed the other two nutrients.
Avoid fertilizers with higher nitrogen levels because they will increase the production of foliage and vines but could prevent the plant from producing blossoms or cucumbers.
Soil Type
Cucumbers will grow in various soil types, but the soil should drain well, be lightweight, and resist compaction for the best results. Heavy clay soils benefit from being amended with organic matter, such as mulch or dried leaves, to lighten the soil and increase drainage.
Cucumbers also prefer soil with a near-neutral pH. The pH scale runs from 0 to 14, with 7 being considered neutral. Numbers higher than 7 are progressively more alkaline, and numbers lower than 7 are increasingly more acidic. In general, the optimal pH for growing cucumbers is between 6.8 and 7.2. Inexpensive pH testers are available from garden centers or online, and they usually come with suggestions for amending soil to either raise or lower its acid-alkaline balance.
Organic vs. Nonorganic
All suitable fertilizers can help the cucumber plant’s growth and production. However, for those who want to use only natural components in their garden, there are organic products available.
- Organic: All the ingredients in an organic fertilizer must be sourced from nature, such as composted poultry manure, worm castings, or bone meal. In addition, the manufacturing process used to create the product cannot use any type of chemicals. A growing number of today’s gardening products are organic.
- Nonorganic: This type of fertilizer may contain synthetic ingredients. It can still produce healthy plants and boost harvests, and it is typically less expensive than organic fertilizers because the manufacturing standards are relaxed.
Our Top Picks
To qualify as a top pick, the following fertilizers had to be within the optimal nutritional range for growing cucumbers, and the products had to be straightforward to use. Some contain synthetic ingredients while others are organic, but all are well suited to boosting cucumber production and overall plant health.
Best Overall
Miracle-Gro 2000422 Plant Food
Pros
- Mixes easily with water
- Contains optimal nutrient ratio
- Designed to promote blossom setting
Cons
- Not organic
The best overall pick in this cucumber-fertilizing lineup is from a brand that’s synonymous with all things gardening. Miracle-Gro Plant Food for Tomatoes and other vegetables is a water-soluble product that can be used with a hose dispenser to spray plant foliage or mixed with water in a watering can and poured on the plant or the soil near the plant’s base.
The granules dissolve quickly, and the fertilizer comes with an NPK ratio of 18-18-21, which is optimal for healthy growth and abundant blossoms. Cucumbers benefit from being fertilized with this Miracle-Gro plant food every 1 to 2 weeks, starting either when the seeds sprout or cucumber seedlings are transplanted into the garden. A 1.5-pound package will fertilize up to 600 square feet of garden.
Product Specs
- NPK ratio: 18-18-21
- Organic or nonorganic: Nonorganic
- Type: Water-soluble
Get Miracle-Gro Plant Food on Amazon, at Menards, or at Lowe’s.
Best Bang for the Buck
Jobe's 09026NA Plant Food Vegetables & Tomato
Pros
- Feeds cucumbers up to 6 weeks
- Contains natural ingredients
- Added beneficial microorganisms
Cons
- Potentially objectionable odor
Those looking for a long-lasting and affordable fertilizer may need to look no further than Jobe’s Organics Vegetable & Tomato Plant Food. The granules are mixed into the top inch or two of soil, where they will gradually dissolve and feed the plants a steady diet of nutrients for up to 6 weeks.
This Jobe’s fertilizer is organic and comes with a 2-5-3 NPK analysis, which is well suited for growing cucumbers. It also contains Jobe’s Biozome, a proprietary blend of beneficial microorganisms and healthy, mushroom-derived bacteria designed to improve the quality of the soil while helping the plants resist insect infestations and disease. Best of all, it comes at an attractive price point.
Product Specs
- NPK ratio: 2-5-3
- Organic or nonorganic: Organic
- Type: Time-release granular
Get Jobe’s Organic Plant Food on Amazon and at Walmart.
Best Organic
Dr. Earth Organic 5 Tomato & Herb Fertilizer
Pros
- Long-lasting
- Contains added micronutrients and trace minerals
- Certified organic by OMRI
Cons
- A bit pricey for coverage
Improve garden soil while giving cucumbers long-lasting nutrients with Dr. Earth’s Organic Fertilizer, which feeds the plants for 3 to 6 months with just one application. Its 4-6-3 NPK analysis is optimal for producing large harvests. The cucumbers may even taste better, thanks to added micronutrients, trace minerals, humic acid, and proteins that provide a wide range of plant nutrients. To top it off, all the ingredients are certified organic by the Organic Materials Review Institute (OMRI), so gardeners can rest assured knowing no synthetic ingredients are included.
One 4-pound bag can cover 60 square feet of the garden when applied as directed, which is less than some other granulated fertilizers cover. This is a premium product that lasts much longer than most, so it doesn’t have to be applied as often.
Product Specs
- NPK ratio: 4-6-3
- Organic or nonorganic: Organic
- Type: Time-release granule
Get Dr. Earth Organic Fertilizer onAmazon, at Walmart, or at Lowe’s.
Best Water-Soluble
Miracle-Gro Water Soluble Plant Food
Pros
- Encourages strong plant growth
- Dissolves quickly
- Can be used in hose dispenser
Cons
- Not organic
This quick-to-dissolve fertilizer mixes easily with water in either a hose dispenser for spraying on the garden or in a pail for pouring over foliage and soil. It features a beneficial 18-18-21 NPK make-up, which encourages strong plant development and helps the plant produce ample blossoms and more abundant harvests.
As a water-soluble fertilizer, this Miracle-Gro plant food is best suited to frequent feedings—every 7 to 10 days—starting when seeds sprout or when transplanting tiny seedlings to the garden. It’s beneficial for use with all garden vegetables as well as herbs. A 2-pound package can fertilize about 800 square feet of garden.
Product Specs
- NPK ratio: 18-18-21
- Organic or nonorganic: Nonorganic
- Type: Water-soluble granules
Get Miracle-Gro Plant Food for Vegetables and Herbs on Amazon, at Walmart, and at Target.
Best for Containers
Jobe's 06028 Fertilizer Spikes Vegetable and Tomato
Pros
- Easy to use
- Lasts up to 6 weeks
- Good for containers
Cons
- Not suitable for large garden plots
Liquid fertilizers can pass through and out of container soil as water drains through the pot and out of the holes at the bottom. These fertilizer spikes from Jobe’s will continuously release more nutrients into the soil every time the plant is watered. The spikes are made from organic nutrients with a beneficial 2-7-4 NPK formula to boost strong root development as well as ample blossom production.
The spikes are easy to use—no need to mix anything with water or work anything into the soil—just press a Jobe’s spike into the soil a few inches away from the base of the cucumber plant. The package comes with 50 spikes, and the recommended usage is eight spikes per square foot of soil. Use when transplanting seedlings and every 4 to 6 weeks after that.
Product Specs
- NPK ratio: 2-7-4
- Organic or nonorganic: Organic
- Type: Time-release spikes
Get Jobe’s Fertilizer Spikes for Vegetables on Amazon, at Walmart or at The Home Depot.
Best Starter Food
Down to Earth Organic Vegetable Garden Fertilizer
Pros
- Lasts up to 1 month
- Added trace minerals
- Organic
Cons
- Slightly pricey
Tender seedlings won’t produce blossoms for quite a while, so a balanced fertilizer with an equal NPK ratio is just the ticket for getting them off to a healthy start. Down to Earth Organic Vegetable Fertilizer comes with a 4-4-4 NPK formula, making it a beneficial plant food for giving young transplants the boost they need. The product also contains the trace minerals calcium, magnesium, and iron and is made from organic ingredients.
This is an all-purpose granular garden fertilizer that can be worked into the soil to improve the growth and harvest of all types of vegetables and herbs. It comes in a 5-pound package, and one container can treat about 100 square feet of garden plants. Down to Earth plant food lasts up to 1 month per feeding.
Product Specs
- NPK ratio: 4-4-4
- Organic or nonorganic: Organic
- Type: Time-release granules
Get Down to Earth Vegetable Fertilizer on Amazon and at Walmart.
Most Complete
Espoma GT4 4-Pound Garden-Tone 3-4-4 Plant Food
Pros
- Long-lasting
- Complete nutrient formula
- All-natural
Cons
- Objectionable smell
Designed for professional gardeners who want to cover all their nutritional bases, Espoma Organic Garden-Tone Herb and Vegetable Food is just the ticket. The granular plant food is enhanced with Espoma’s Bio-tone microbes and contains 15 essential nutrients so plants won’t lack anything needed for growth. The product will fertilize garden plants for up to a month or longer, and the granules break down slowly to provide a continuous supply of nutrients.
The microbe in the mix is beneficial for the plants, and it also helps improve garden soil for future plantings. It features an ideal 3-4-4 NPK analysis and is best applied at the rate of a half cup per plant, worked into the ground near the plant’s drip line.
Product Specs
- NPK ratio: 3-4-4
- Organic or nonorganic: Organic
- Type: Time-release granules
Get Espoma Organic Garden-tone on Amazon, at The Home Depot, and at Walmart.
Also Consider
Element Nutrients Flower Fuel The Best Bloom Booster
Pros
- Produces abundant blossoms
- Heavy harvests
- Dissolves quickly in water
Cons
- Not organic
Gardeners looking for heavy harvests need to look no further than Flower Fuel’s Super-Premium Bloom Booster that encourages maximum blossom production for large cucumber yields. Perfect for growing cukes for farmers’ markets or sharing with family and friends, Flower Fuel is the fertilizer to use when the first blossoms appear on the plant. Until then, an all-purpose fertilizer is better suited to get the plant off to a healthy start.
Flower Fuel features a powerful 1-34-32 NPK analysis, which encourages blossoms and helps develop the fruits themselves. This low-nitrogen fertilizer focuses on cucumber production rather than abundant foliage. The proprietary blend contains more than 40 ingredients, including various vitamins, nutrients, and minerals. It quickly dissolves in water, and a single 8.7-ounce package produces 200 gallons of fertilizer-rich water. It can also be used in hydroponic systems.
Product Specs
- NPK ratio: 1-34-32
- Organic or nonorganic: Nonorganic
- Type: Water-soluble powder
Get Flower Fuel Super-Premium Bloom Booster on Amazon.
Our Verdict
Considered among the best cucumber plant food products on the market, any fertilizer and plant food pick in this lineup can help growers produce healthy cucumbers. However, Miracle-Gro for Vegetables is our top choice for its beneficial NPK formula and the manufacturer’s solid reputation. If budget is a major factor in choosing a fertilizer, consider Jobe’s Plant Food for Vegetables and Tomatoes as it’s a top pick for affordability and long-lasting time-release feedings.
How We Chose the Best Fertilizer for Cucumbers
To make the cut for this lineup, the fertilizer first had to provide an NPK analysis that was either balanced or had less nitrogen (N) than phosphorus (P) and potash (K). Any products with a higher nitrogen content were eliminated right away because cucumbers don’t produce well in soil with high nitrogen levels, tending to make all leaves but few, if any, blossoms.
We also looked at brand reputation. It’s hard to beat brands like Miracle-Gro based on reliability and quality. However, we didn’t eliminate fertilizer products if they met our guidelines but were manufactured by smaller (or niche) companies. In addition, the fertilizer product had to be well-liked by other consumers who used them and found them beneficial. Plus, the fertilizer had to be simple to use.
FAQs
Cucumbers are among summer gardens’ favorite treats, and feeding them with optimal plant food will keep them healthy and encourage large, tasty cucumber harvests. Many new to growing this delicious fruit may have questions, such as: “What is the best fertilizer for cucumbers?” and “Can a fertilizer designed for other garden plants also be the best fertilizer for cucumber plants?” Below are answers to some of these popular questions.
Q. When should I fertilize my cucumbers?
It depends on the fertilizer you choose. However, the general rule of thumb is to fertilize when you transplant seedlings into the garden or containers, and then every few weeks, according to the product’s instructions.
Q. Should I fertilize my cucumber plants?
Probably. It’s best to fertilize cucumber plants unless you’re planting them in containers filled with potting soil that comes already amended with a time-release fertilizer.
Q. Is Epsom salt good for cucumber plants?
Epsom salt provides vital magnesium if the soil is magnesium deficient. Before adding it, however, take a sample of the soil to your local agricultural extension office for testing. Depending on the results, it will advise on whether adding Epsom salt will be beneficial for growing cucumbers.
Q. What kind of fertilizer should I use for cucumbers?
Most vegetable and tomato fertilizer types are suitable, but be sure to select a fertilizer where the nitrogen (N) content is equal to or less than the other numbers in the NPK ratio. For example, 5-6-8 NPK or 3-3-3 NPK.
Q. Can tomato fertilizer be used for cucumbers?
Most of the time, yes, tomato fertilizer can be used for cucumbers. Just check the NPK ratio to ensure the nitrogen (N) isn’t higher than the other numbers.
Q. How can I grow cucumbers in containers?
Select a well-drained potting soil, but avoid filling containers with garden soil because it tends to compact, which reduces root growth. Water frequently to keep the soil moist and fertilize regularly.
Q. How much nitrogen can I put on my vegetable garden?
Some nitrogen is OK, but for most vegetables, the general rule is to select a fertilizer where the nitrogen (N) content is equal to or less than the amount of phosphorus (P) and potash (K). The best fertilizer for tomatoes and cucumbers will encourage healthy plant growth, boost root development, and promote blossom and fruit production.
