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How To Fertilize Cucumber Plants For Your Best Harvest Ever!

When it comes to growing healthy, long-living and productive cucumber plants, how and when you fertilize really does make all the difference!

Cucumbers are one of the most popular of all vegetable plants to grow at home. Perhaps it’s because you can grow them almost anywhere – whether it be in a traditional garden setting, raised beds, pots and containers, or even in straw bales if desired.

No matter where or how you grow cucumbers, they need a steady supply of nutrients to survive and thrive. Especially as the growing season wears on, and your plants begin to grow and produce.

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The fact is, cucumber plants use a lot of nutrients from the soil as they develop their foliage and blooms. And without help in the form of additional nutrients, many plants never reach their full potential. And that is exactly where giving them a boost of energy can help!

Here is a look at when and how to fertilize your plants, and a few of the best options to use when doing so.

How To Fertilize Cucumber Plants

When it comes to successfully fertilizing cucumbers, it really boils down to giving them nutrients at 3 different points and stages.

  • At Planting Time
  • When Mulching Around The Plants
  • At 2 Week Intervals As They Develop

Here is a look at each fertilizing stage, and how to power your plants for maximum production and health.

planting cucumbers
Fertilizing as you plant transplants or seeds is one of the 3 key times to boost plants. Providing young plants with easy to absorb nutrients right around their roots helps get them off to a great start.

Starting Plants Off Right – How To Fertilize Cucumber Plants

Success with growing cucumbers begins with getting them off to a great start on planting day. And the best way to do that is to give them a boost of nutrients right in their planting hole.

How you fertilize will depend on if your planting seeds, or transplants. When planting seeds, it’s important to first mix in generous amounts of compost to the soil.

How much compost? A good rule of thumb is to create your planting hole or mound from 50% soil, and 50% compost.

Compost truly is the perfect, all-natural, fully-balanced, slow release fertilizer. Not only does it teem with minerals and beneficial organisms, it also helps to retain moisture in the soil. And that moisture is important for helping seeds germinate and grow quickly.

fertilizing with worm castings
Worm castings are one of the best all around low and slow fertilizers you can use. They are 100 percent organic, and release their power slowly but easily to plants.

When planting transplants, once again, compost is the answer. Dig your transplant holes to about 3 times the size of your root ball. Then fill in the hole with a 50/50 mix of soil and compost to build in ready-to-go nutrients for your plants.

Want to provide even more of a boost at planting time? Add in a quarter to a half cup of worm castings to your planting hole as well.

Worm castings provide a slow, balanced supply of nutrients that are easily absorbed by the plant’s roots. And will they ever get your young transplants off to an incredible start!

Mulching With Power – How To Fertilize Cucumber Plants

As soon as you plant your transplants, or as soon as your seeds pop through the earth, it’s time to mulch. Mulch not only helps to keep weeds under control, it also helps to regulate soil temperature. Both are two big keys for growing healthy, productive plants. (See : How To Grow Great Cucumbers)

But here is a little secret that can help your plants even more – add power to your mulch in the form of a bit of fertilizer!

mulching vegetable plants with compost
Mulching your cucumber plants is a must to help control weeds, protect the vegetables as they develop, and regulate soil temperature. But it also gives you a great opportunity to provide your plants with more nutrients.

When mulching plants, apply a 2 inch thick layer of compost about 6 inches in diameter as a first layer of mulch around each plant. And while you are at it, mix in a quarter cup of worm castings to the compost as well! Then apply your regular mulch ( straw, shredded leaves, etc.) as normal.

This “ring” of compost and castings will act as the ultimate slow release fertilizer every time you water or it rains. Nutrients will slowly leach into the soil below, giving the plants instant but balanced power to grow.

Powering Young Cucumber Plants – How To Fertilize Cucumber Plants

Once your plants are in the ground and established, the next step is to begin providing them with regular, but light applications of fertilizer as they develop. And those two key words, regular and light make all the difference!

Provide your plants with no additional fertilizer after planting and they will likely under-perform. But give them too much, and all they will do is produce foliage, and little cucumbers.

fertilizing cucumber plants
Fertilizing plants on a regular basis with a light dose of liquid fertilizer is a big key to growing success. When mixing liquid fertilizers, use them at half strength to provide a slow, steady supply of nutrients.

When any vegetable plant receives too frequent or too much fertilizer, they use the excess energy to grow foliage, not blooms. The result is a massive plant with little production. And, if too much is used, it can even result in the plant dying off.

And that is exactly why regular but light applications of fertilizer work best. They give plants a steady dose to keep them producing blooms, but not so much that they grow only foliage.

How To Fertilize Young Plants – How To Fertilize Cucumber Plants

For best results, once your cucumber plants have established, fertilize with a light dose of liquid organic fertilizer every two weeks for a total of an 8 week period. (4 applications)

What does “established” mean? If planting transplants, it means giving the plants 7 to 10 days to adjust their roots into the soil before fertilizing. For seeds, it means allowing them to grow enough that the seedlings are at least a few inches high and have developed 3 to 5 leaves.

liquid fertilizer
Liquid fertilizers are absorbed through both the leaves and roots. This double action really helps plants get what they need to grow.

You also might ask, why a liquid fertilizer? Because liquid fertilizers work in two ways. They are absorbed by the leaves of the plants, and through the roots. This double action allows plants to get more nutrients at a much better rate than by using granular fertilizers.

As for the light dose, simply cut back on the strength of the fertilizer by diluting it. If using a commercial organic fertilizer, mix it at half strength. If using compost tea or worm casting tea, cut the strength in half with more water as well.

Knowing When To Back Off – How To Fertilize Cucumber Plants

Finally, once plants begin to fully produce, it’s time to back off on the fertilizing, and concentrate your efforts on harvesting.

Once plants begin to fill with fruits and blooms, no more fertilizing is necessary. In fact, it can hurt later production by making the plants put all their energy into creating more leaves, and not blooms.

And harvesting regularly is important to your plants production levels too! Cucumber plants, like many vegetable plants, will suffer from what is known as fruit overload. Meaning, there are too many ripe cucumbers on the vines.

When this occurs, it is a signal to plants to stop producing new blooms so they can concentrate on ripening fruit. So keep picking those cucumbers and watch the harvest totals grow! Here is to fertilizing your cucumbers with gusto this year, and to having your best crop ever.

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