Hydroponic Plant Pairing Charts

By: Chris | Last Updated: January 13, 2021

Tired of growing the same plants all the time? Want to know how to pair plants in the same hydroponic system? Use the plant pairing charts below to grow a harmonious hydroponic garden.

If you’re interested in seeing how I pair plants, check out the sections after the charts. I might even share a story about a poor little arugula plant 🤣

Apera Instruments PC60 Waterproof pH/EC Tester Kit
$132.00

I've been using this kit for about 8 months and love it. It comes with everything you need to keep the tester calibrated and highly accurate.

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06/13/2021 01:47 am GMT

Hydroponic Plant Pairing Chart
EC 0.8-1.8


Color Coding For Daily Light Requirements
Orange 12-14hrs | Green 6-8hrs | Blue 8-10hrs | Red 14-18hrs

On Mobile? Rotate to horizontal “widescreen” view for best presentation.

Plant pH Range EC Range
5.5-6.0 6.0-6.5 6.5-7.0 .8-1.2 1.2-1.6 1.6-1.8
Artichoke . . x x x x
Arugula . x x x . .
Asparagus . x . . x x
Chives . x . . . x
Cilantro x x . . x x
Coriander x x . . x x
Cucumber x . . . . x
Dill x x . . x x
Fennel . . x . x .
Garlic . x . . x x
Lavender . . x . x .
Lemon Balm x x . x x .
Lettuce x x . x . .
Onions . x . . x x
Oregano . x x . . x
Sage x x . . x x
Spinach . x x . . x
Sweet Corn . x . . . x
Thyme x x x x x x
Watercress . . x x x x
Plant 5.5-6.0 6.0-6.5 6.5-7.0 .8-1.2 1.2-1.6 1.6-1.8
Anise x x . x x .
Beatroot . x . x x x
Bok Choy . x x . x x
Celery . . x . . x
Chamomile x x . . x .
Chervil x . . x x x
Parsley x . . x x x
Rosemary x . . . x x
Broad Bean . x . . . x
Catnip x x . . x .
Cauliflower . x x x x x
Kale x x . . x .
Mustard Cress . x . . x x
Pea . x x x x x
Pea (Sugar) . x x x x x
Radish . x x . . x
Tarragon x x . . x x
Plant 5.5-6.0 6.0-6.5 6.5-7.0 .8-1.2 1.2-1.6 1.6-1.8
Basil x x . . x .
Capiscum . x . . . x
Carrot . x . . . x
Fodder . x . . . x
Leek . . x . x x
Marrow . x . . . x
Parsnip . x . . x x
Tomato x . . . x x

Hydroponic Plant Pairing Chart
EC 2.0-5.0


Color Coding For Daily Light Requirements
Orange 12-14hrs | Green 6-8hrs | Blue 8-10hrs | Red 14-18hrs

On Mobile? Rotate to horizontal “widescreen” view for best presentation.

Plant pH Range EC Range
5.5-6.0 6.0-6.5 6.5-7.0 2.0-2.5 2.5-3.0 3.0-5.0
Bean (Common) . x . x x x
Broccoli . x . . x .
Chives . x . x . .
Cucumber x . . x . .
Okra . . x x . .
Oregano . x x x . .
Potato x . . x . .
Pumpkin x x x x . .
Spinach . x x x . .
Sweet Corn . x . x . .
Plant 5.5-6.0 6.0-6.5 6.5-7.0 2.0-2.5 2.5-3.0 3.0-5.0
Beatroot . x . x x x
Bok Choy . x x x . .
Brussell Sprout . . x . x .
Celery . . x x . .
Chickory x . . x . .
Mint x . . x . .
Broad Bean . x . x . .
Eggplant x x . x x .
Mustard Cress . x . x . .
Taro x . . . x .
Plant 5.5-6.0 6.0-6.5 6.5-7.0 2.0-2.5 2.5-3.0 3.0-5.0
Cabbage . . x . x .
Endive x . . x . .
Marrow . . x x . .
Pepino . x . x x x
Peppers x x . x x .
Peppers (Bell) . x . x x .
Peppers (Hot) x x . . . x
Silverbeet . x x x . .
Tomato x . . x x .
Turnip . x . x . .
Zucchini . x . x . .

Pairing by Nutrient & pH Needs

Pairing plants that have similar nutrient and pH needs is a good way to begin planning for an upcoming grow. This list of EC & pH levels for hydroponic plants and herbs can help expedite this stage of the planning process.

Every gardener has their preferred growing and pairing methods, and I’m no different. I love experimenting with different nutrient and pH levels. My preference is to pair plants that have very closely related pH and EC ranges. This allows me to start with a low pH and relatively high EC.

Pair plants that have overlapping pH & EC ranges.

General Hydroponics pH Control Kit
$17.30
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06/12/2021 05:02 pm GMT

Experiment with different pairings, don’t take the pairing tables below as “set in stone” rules. Break the rules, learn new things for yourself! That’s part of the fun.

For instance, I’m currently growing lettuce, spinach, and arugula in the same system. That isn’t a super-radical idea.

Each plant has similar photoperiod requirements, overlapping pH ranges, and fairly close nutrient requirements. The only immediately obvious disparity is that spinach would receive around 33% less than the minimum recommended nutrient level.

What I’ve found is that lettuce and spinach both produce very well at a pH of 5.5 and a 1.7 EC. What I also found is that arugula is NOT happy with those conditions. I say all that to recommend that you always experiment and try new things!

That experiment taught me that arugula may be spicy, but it ain’t very tough when it’s out of its element! I promise I’ll take better care of you next time my little friend.

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06/12/2021 04:28 pm GMT
Hydroponic Arugula Not Happy With High EC Levels
Poor little arugula 😢

Pairing by Plant Characteristics

Pairing plants based on growing characteristics is also important. It would be hard to grow carrots and peppers in the same hydroponic system. Peppers grow tall and bush out, and would quickly block light from carrots.

Pair plants based on their hydroponic system requirements, how tall they grow, how much room they need, and how much light per day they require. Couple this with the nutritional and pH needs listed above, and you’ll be pairing plants in no time!

Let me know what you think!

I put together these charts to help you pair hydroponic plants in a visual way. Don’t think of these are rigid rules, but rather as rough guidelines. Make sure to bookmark this page so you can easily reference it in the future!

Let me know how you like the charts, and if there are any other tools you’d like for me to make available here. I love hearing from you!

Chris Cook started Happy Hydro Farm to share his passion for hydroponic gardening! Growing your own food is incredibly rewarding both physically and mentally. His mantra - "Take excellent care of your plants, and your plants will take excellent care of you."