Growing a Variety of Fruits and Vegetables with Hydroponics

Many people ask about growing different types of fruits and vegetables together, when growing with hydroponics.  When growing fruits and vegetables with hydroponics, you will generally grow fastest if you stay within the recommended PPM and pH range for individual plants (see below).  However, your plants will still grow well outside of those ranges.  The most basic impacts of growing outside of those ranges are:

  • Less food production
  • Changes to the taste of produce

We try to provide cherry tomatoes, herbs and lettuce when iHarvesters are just beginning to grow because it's a great way to learn about the trade-offs and personal preferences involved.  Many herbs and lettuce varieties grow best at lower PPM levels of ~600-800 PPM (although several do well at higher PPM levels as well).  Tomatoes, on the other hand, prefer much higher PPM levels of 1,400 - 3,500 PPM.  My suggestion is to start growing everything at 600-800PPM.  What you will discover is that everything grows well, but your tomatoes will be very slow to produce flowers and ultimately fruit.  After harvesting your first batch of lettuce and herbs, you can increase your PPM to 1,000.  At this point, your tomatoes are likely to begin slowly producing flowers and fruit.  The same can be said for other fruiting plants like cucumbers.  However, you may notice changes to the taste of your herbs and lettuce.  Lettuce, for instance, may start to taste more bitter.  Depending on your taste buds and your preferences, you can manage your PPM up or down, and choose different varieties of fruits and vegetables to grow based on the chart below.

You may notice other issues caused by growing plants outside of their optimal PPM range.  For example:

  • At lower PPM’s tomatoes and cucumbers can become more susceptible to disease like ‘powdery mildew’ disease
  • At lower PPM’s, some pepper plants will not be able to produce healthy fruit
  • At higher PPM’s some lettuce varieties will have ‘tip burn,’ which makes the edges of the lettuce look burnt

Growing plants that are all within the same PPM range will always be the safest and fastest route.  If you want to grow tomatoes and peppers at higher PPM levels, but also want leafy greens, consider replacing your lettuce with spinach, because spinach prefers higher PPM levels.

However, experimenting with the method described above may also allow you to find a more creative balance of fruits and vegetables that you enjoy growing.

Nutrient and pH Chart for Hydroponic Gardens

Plant

pH

EC

PPM

 

 

 

 

Basil

5.5-6.5

1.0-1.6

700-1120

Bean (Common)

6.0-6.0

1.8-2.4

1400-2800

Bean (Broad)

6.0-6.5

1.8-2.4

1400-1800

Bell Peppers

6.0-6.7

1.8-2.8

1400-2000

Broccoli

6.0-6.5

2.8-3.5

1960-2450

Brussell Sprouts

6.5-7.5

2.5-3.0

1750-2100

Cabbage

6.5-7.0

2.5-3.0

1750-2100

Cauliflower

6.0-7.0

0.5-2.0

1050-1400

Celery

6.3-6.7

1.8-2.4

1260-1680

Chives

6.0-6.5

1.8-2.4

1260-1680

Cucumber

5.8-6.0

1.7-2.5

1190-1750

Eggplant

5.5-6.5

2.5-3.5

1750-2450

Lavender

6.4-6.8

1.0-1.4

700-980

Lemon Balm

5.5-6.5

1.0-1.6

700-1120

Lettuce

5.5-6.5

0.8-1.2

560-840

Melon

5.5-6.0

2.0-2.5

1400-1750

Mint

5.5-6.0

2.0-2.4

1400-1680

Pak-choi

7

1.5-2.0

1050-1400

Parsley

5.5-6.0

0.8-1.8

560-1260

Pea

6.0-7.0

0.8-1.8

580-1260

Peas (Sugar)

6.0-6.8

0.8-1.9

580-1261

Peppers (Bell)

6.0-6.5

2.0-2.5

1400-1750

Peppers (Hot)

6.0-6.5

2.0-3.5

1400-2450

Pumpkin

5.5-7.5

1.8-2.4

1260-1680

Sage

5.5-6.5

1.0-1.6

700-1120

Spinach

5.5-6.6

1.8-2.3

1260-1610

Squash

5.0-6.5

1.8-2.4

1260-1680

Strawberries

5.5-6.5

1.0-1.4

500-700

Swiss Chard

6.0-6.5

1.8-2.3

1260-1610

Thyme

5.5-7.0

0.8-1.6

560-1120

Tomato

5.5-6.5

2.0-5.0

1400-3500

Watercress

6.5-6.8

0.4-1.8

280-1260

Watermelon

5.8

1.5-2.4

1050-1680

Zucchini

 6.0

1.8-2.4

1260-1680

 

There's more great growing information in the links below:

Let’s Grow Together!


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