What is the correct EC for growing?

plants being cared for in a garden
Published: 18 March 2025

Electrical conductivity measurement is an important part of gardening if you’d like to achieve healthy plant growth. Alongside pH, testing EC with a soil tester can help you stay within the most suitable range for your particular plant type, ensuring the necessary nutrients are present for successful growing. Read on to learn more about the correct range for EC in plants below:

How does EC affect plants?

EC, or electrical conductivity, measures how effectively a substance transmits a current of electricity. In agriculture and gardening, measuring the EC level provides information about the amount of nutrients that are available by determining the number of ions within the soil. In combination with pH, EC is a valuable parameter to check in soil as the concentration of nutrients affects the health and growth of your flowers, vegetables and herbs.

EC is affected by a wide range of different factors, including:

  • Temperature changes
  • Soil type
  • Moisture level
  • Irrigation
  • Fertilisers
  • Soil depth

How do you measure EC in the soil?

A direct digital conductivity tester for soil is the ideal option to measure this parameter in your garden. These simple testers allow you to measure the soil conductivity with no need to remove a sample for testing. Regularly measuring the soil with a garden EC tester provides the insight needed to make any adjustments to nutrient levels, helping your plants to thrive.

Hanna’s range of testers includes soil meters such as the HI-98331 Groline EC and temperature tester, providing an easy way to measure soil conductivity directly. This pocket tester includes a replaceable probe and has automatic temperature compensation for accuracy in testing. To learn more about testing EC, see our complete guide here.

How can you change the EC of the soil?

Once you have an accurate, digital measurement of the EC of your soil, you can take the necessary steps to bring this parameter into the suitable range. Dilution can be used to lower EC by introducing pH-balanced water and allowing it to flush some of the nutrients away. To increase EC, you can introduce more nutrients with an additive or fertiliser. It’s important to measure your EC again after attempting to increase or lower this parameter to ensure it is within the right range for your requirements.

Do all plants need the same EC range?

Different plants have different requirements for EC range, from watercress with a very low preferred range to carnations with a higher preferred range. Understanding the specific requirements of the plants you’d like to grow can help you achieve the best outcome. See the optimal conductivity ranges for some of the most commonly grown plants below.

Optimal EC levels of different plants

African Violet

1.0-1.2

Iceberg Lettuce

0.6-1.4

Artichoke

1.4-1.8

Lavender

1.0-1.5

Asparagus

1.4-1.8

Leek

1.4-1.8

Aster

1.8-2.4

Mint

2.0-2.4

Aubergine

2.5-3.5

Mustard

1.2-2.4

Basil

1.0-1.6

Onion

1.8-2.2

Beans

1.8-2.5

Parsley

1.0-2.0

Beetroot

1.4-2.2

Parsnip

1.4-1.8

Begonia

1.4-2.4

Pea

1.4-1.8

Blueberry

1.8-2.0

Pepper

2.0-2.5

Broccoli

1.8-2.4

Potato

2.0-2.5

Brussels Sprouts

1.8-2.4

Pumpkin

1.8-2.4

Cabbage

1.8-2.4

Radish

1.6-2.3

Carnation

2.0-3.5

Rhubarb

1.6-2.0

Carrot

1.4-2.2

Roses

1.5-2.5

Cauliflower

1.5-2.0

Sage

1.0-1.6

Courgette

1.8-2.4

Spinach

1.8-2.3

Celery

1.8-2.4

Squash

1.8-2.4

Chives

1.5-2.5

Strawberry

1.8-2.2

Cucumber

1.7-2.5

Thyme

1.0-1.5

Dahlia

1.5-2.0

Tomato

2.0-5.0

Fennel

1.0-1.5

Turnip

1.8-2.4

Gerbera

2.0-2.5

Watercress

0.4-1.8

Buy garden EC testers from Hanna

Hanna’s comprehensive range of testers includes easy, handheld digital EC testers for gardening, like the HI-98331 Groline direct soil EC tester, as well as a wide range of nutrient testers for hydroponics. Shop the full range of conductivity testers for gardening online today.

Agriculture
Gardening
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