Growing Hydroponic Cucumbers


Cucumber is simply delicious.  It’s great as a healthy snack and it’s wonderful on a fresh salad.  And, whether you have too many cucumbers or not, pickling your cucumbers is always going to be a treat.  Don’t forget that it’s also great for making delicious coleslaw and cucumber mint water as well.  Hydroponic Cucumbers can certainly be more difficult to grow successfully than peppers and tomatoes, for example, so we suggest not growing cucumbers too early in your hydroponic journey.  Their frequent need for calcium supplementation and their susceptibility to powdery mildew are two reasons why they can be more difficult to grow.

There are an enormous number of cucumber varieties.  There are normal varieties and there are dwarf varieties.  Keep in mind that some dwarf varieties don’t really save a whole lot of space, because while the fruit is smaller, the leaves are just as large as usual. There are also parthenocarpic cucumbers, which do not need pollination to bear fruit.  And there are some cucumbers that are known for being better for pickling than others (these are usually the ones with bumps on them).  IGWorks® has several cucumbers available on its website, but as always, you can use any seeds you’d like to grow with our products.

Hydroponic Cucumbers
Difficulty Light EC Range They need additional calcium and potassium Time to Harvest
Intermediate 16 hours 1.8 - 3.0 5.8 - 6.5 2-3 months
Nutrient and Health Info - Cucumbers have a low glycemic index of 15, meaniing they are not likely to raise blood sugar. As a non-starchy vegitable,they are also good at satisfying appetities. A natural antioxidant with anti-inflammitory properties.
Tips & Tricks - Most varities need to be pollinated. A small makeup brush works great. Folks often add additional trellises next to the iHarvest to allow them extra room to grow. Consider adding additional Calcium and Potassium, as they flower prolifically. Grows well with tomatoes and peppers. Early male flowers will not produce fruit, so be patient.



Cucumber grows well from seed. It won’t hurt to propagate your cucumber seeds directly in the iHarvest.  But, if you believe caution is the better part of valor, you can use our Seedling Starter Kit, or the paper towel method for even better results. You can make your own seedling starter kit by using Tupperware covered with plastic wrap that you poke a few holes in.


Cucumbers, like most fruit, like lots of light.  Your cucumber will perform best when receiving 16 hours of artificial light.  This ensures that your plants will flower frequently, and they have enough energy to produce mature fruit.

EC Range:

Your iHarvest® comes with an EC tester.  EC stands for ‘Electrical Conductivity’ and it is a measure of the nutrients in your water solution.  When growing cucumbers, you will want to keep your EC range between 1.8 and 3.0 for optimal growth.  Cucumbers grows well with other plants that grow well in these PPM ranges, such as eggplants, peppers, tomatoes and even cabbage. 

pH Range:

Your iHarvest® comes with a pH tester.  Adjusting your pH allows your plants to absorb the nutrients they need, as efficiently as possible.  Keep your pH between 5.8-6.5 for optimal growth.


Cucumbers is a flowering/fruiting plant.  When they are young, before they begin flowering, your cucumber plants will thrive with a general nutrient mix for vegetation, like IGWorks’ Green Machine Nutrients.  When your cucumbers flower, you will want to add at least 50% Flower Power Nutrients to the mix. 

An important note on Calcium: One of the things that makes cucumbers more complicated than many other plants is that their nutrient requirements can be more complex.  Often while growing cucumbers, you will find that the edges of your leaves look scorched.  Sometimes you will see white spots scattered on the leaf’s surface.  These are signs of a calcium deficiency when they occur in younger leaves (sometimes older leaves just age this way over time).  Adding calcium will help.  Start by adding 0.3 - .04 EC of calcium to your reservoir, while keeping your total EC range between 1.8 and 3.0.

An important note on Potassium (K):  Cucumbers flower prolifically, and flowers require potassium.  If your cucumbers are having trouble setting fruit, or the fruit aborts quickly, they may have a potassium deficiency.  consider adding 1/4 teaspoon of a 0-0-50 nutrient mix for every 10 gallons of water in your system to help your cucumbers flower, fruit and grow.  Keep your total EC range between 1.8 and 3.0


While there are parthenocarpic cucumber that are self-fertile, most cucumber need some help.  Using a small art or makeup brush to pollinate female flowers (they look like mini cucumbers) with male flower pollen is needed.  We have a whole article dedicated to pollinating your plants here, if you’d like to review in more detail.


Removing dead leaves allows more light to reach those that are alive.  You can also train your plant by trimming the vines that are reaching where you don’t want them to grow.  Also make sure to remove cucumber fruits that are stunted and not growing, to provide additional nutrients for those that are growing well.

But perhaps most important is keeping an eye out for common issues that occur with cucumbers.  Powdery Mildew is quite common, and can be a real nuisance.  Check this article on powdery mildew to learn more.  And, keep an eye out for calcium deficiencies as described in the nutrient section of this article.


It’s not always obvious when to harvest your cucumbers, but in general you want to do so before white lines become too pronounced or there are any signs of yellowing.  Check your seed packet to determine what size your cucumber is supposed to be for harvesting. 

Cucumber and tomato

Time to Harvest:

Cucumbers usually require 2-3 months to harvest, after planting seeds.  It will often take less time, especially when managing your nutrients, pH and EC as described above.


Remember, you don’t require a green thumb to grow hydroponic cucumbers in the iHarvest®.  In fact, it’s easier than growing in soil.  The more closely you follow the directions, the more cucumbers you will have.  And don’t forget, IGWorks® and the Indoor Garden Works Group on Facebook are always here to help.

Check Out Our Cucumber Recipes!

Let's grow together!