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 EC 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

Growing cherry tomatoes, herbs and lettuce when iHarvesters are just beginning to grow is a great way to learn about the trade-offs and personal preferences involved.  Many herbs and lettuce varieties grow best at lower EC levels of ~0.9 -1.2 (although several do well at higher EC levels as well).  Tomatoes, on the other hand, grow fastest and produce more fruit at higher EC levels of 2.0 – 5.0.  My suggestion is to start growing everything at 0.9 – 1.2 EC when you are just starting out.  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 EC to 1.5.  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 or may not notice changes to the taste of your herbs and lettuce.  Lettuce, for instance, may begin to taste slightly bitter.  Depending on your own taste buds and preferences, you can manage your EC up or down from there, 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 EC range.  For example:

  • At lower EC’s tomatoes and cucumbers can become more susceptible to disease like ‘powdery mildew’ disease
  • At lower EC’s, many plants will not be able to produce significant amounts of fruit
  • At higher EC’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 EC range will always be the safest and fastest route.  If you want to grow tomatoes and peppers at higher EC levels, but also want leafy greens, consider replacing your lettuce with spinach, because spinach prefers higher EC 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.

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Nutrient and pH Chart for Hydroponic Gardens

Plant

pH

EC

(Preferred over PPM)

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

1.8-3.0

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

5.0-5.5

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:

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