Growing Hydroponic Bok Choy – A Full Guide

Introduction: Hello gardeners today we are back with a very good information of growing hydroponic Bok Choy. Bok Choy is sometimes called white cabbage, not to be confused with Napa cabbage, which is also a type of Chinese cabbage. Several kinds of Bok Choy vary in color, taste, and size, including tah tsai and joi choi.

A step by step guide to growing hydroponic Bok Choy

Bok Choy, like many Brassicas, can be grown hydroponically successfully. It is a rapidly maturing crop that can be harvested in 30 days from germination. If executed correctly you can obtain 3 harvests from one set of Bok Choy roots. There are several Bok Choy varieties for example green stemmed, red leaf variations, as well as many that have the familiar white stem. In this article we also cover the following topics;

  • Hydroponic Bok Choy nutrient requirements
  • How long does it take to grow Bok Choy in hydroponics
  • Advantages of growing plants by using hydroponics
  • Hydroponic Bok Choy growing conditions
  • Optimal pH for Bok Choy growing hydroponically
  • Growing Bok Choy in bucket hydroponic system

Bok Choy growing conditions

Deficiencies in Bok Choy can be difficult to identify, as the more “dramatic” symptoms such as inter-veinal chlorosis, burning, or bronzing are not common. Deficiencies are marked by stunted growth, cupping, and yellowing.

Bok Choy Growing Conditions.
Bok Choy Growing Conditions.

Plant Bok Choy from seed and transplant as soon as there are true leaves on the plant; this will typically occur in about 4 weeks. Though the highest yields occur at 6 weeks from transplant, Bok Choy can be grown on shorter turns down to four weeks.

Bok Choy plant has thick but fragile veins and ribs; take care when handling not to break leaves. And store Bok Choy in containers with good air circulation and high relative humidity, at temperatures in the 30s (º F), or just above freezing.

Hydroponic garden systems

Hydroponics is a form of gardening that uses no soil, but instead of soil plants grow in a solution of water and nutrients. The first step to setting up a hydroponic garden is selecting a system that fits your needs. Important factors to consider how much space you have, what you want to grow, cost, and the amount of time you have to spend maintaining the system.

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Wick systems

Wick systems are the simplest system mechanically and the easiest to set up as there are no moving parts. The system consists of a reservoir filled with water and nutrients; above it, there is a container filled with a growing medium. The two containers are connected by a wick, which draws the nutrient-filled water up into the growing medium where it is absorbed by the plant roots. This system is great for learning the basics, but it could not work well with large plants or with water-hungry plants like lettuce because the wick cannot supply water fast enough. Though, this system works well with microgreens, herbs, and peppers.

Aggregate systems

Aggregate systems use some form of inert material to support and surround roots. The common materials used are rock wool, clay pebbles, and gravel, perlite, vermiculite, sand, or foam chips. One of the common systems using aggregate media is the flood and drain method.

A water-holding container, such as a plastic dishpan, filled with the aggregate and plants. And the container is flooded periodically with the nutrient solution. The solution is drained back into the nutrient reservoir by opening a valve at the container bottom. During each cycle, the roots must be submerged in the solution for no more than 20 to 30 minutes. Another aggregate system is the trickle feed method. The nutrient solution is pumped from the reservoir through about 1/2-inch irrigation tube that branches into several 1/8-inch tubes. These smaller irrigation tubes deliver the solution to the containers. Any excess solution is collected at the base of the container and returned to the nutrient reservoir.

Water culture systems

A water culture system is a simple system to set up. In this system, the plants are located in a Styrofoam platform that sits on top of the reservoir holding the solution of water and nutrients. A bubbler air pump is added to the reservoir to deliver oxygen to the roots. This system is suited for water-hungry plants but it is not as well-suited for more long-lived plants, such as tomatoes.

Drip systems

Drip systems are probably the widely used type of hydroponic system in the world. A timer controls a submersed pump. The timer turns the pump on and nutrient solution is dripped onto the base of the plant by a small drip line.

Ebb and flow systems

Ebb and flow systems are slightly complex in design, but they are extremely versatile. This system works by flooding the growing medium with a water-nutrient solution and draining it back into the reservoir. To do this, the system wants a submersible pump with a timer. One of the greatest advantages of the ebb and flow system is that you can use the timer to customize your plants’ watering schedule based on their size, number, ambient temperature, and humidity, etc. You have the option of potting plants individually for easy customization or filling the entire tray with growing medium and planting directly in the tray.

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Temperature conditions for growing hydroponic Bok Choy

Grown in soil Bok Choy fares well under cool conditions, temperatures of 50 to 70ºF but survive in lower temperatures. High-temperature ranges have been known to cause Bok Choy to prematurely bolt to seed. Once it bolts to seed the leaves are low quality and in many cases fit only for the compost heap.

The same temperature requirements apply to hydroponically grown Bok Choy. The difference relative to temperature in hydroponic Bok Choy is the water temperatures which will affect the amount of oxygen the water is capable of retaining. A higher reservoir temperature range will impede oxygenation.

That should keep the solution slightly lower than the air temperature. Where the air temperatures can be held at 50-70ºF, the water temperature range should not exceed 65ºF at most.

Growth requirements for growing Bok Choy

Whether a plant is grown in soil or a soilless medium, there are several factors affecting plant growth and productivity. All plants need nutrients, water, light, and air to grow. A plant grown in soil obtains nutrients and water from the soil, when obtainable. With a hydroponic system, because water and nutrients are always available, the plant is never stressed. Sunlight and air are readily obtainable in an outdoor hydroponic system. However, for an indoor system, one must give an adequate light source and good air circulation.

Bok Choy Growing Requirements.
Bok Choy Growing Requirements.

Metal halide lamps, sodium vapor lamps, grow-lights, or fluorescent lights used in conjunction with incandescent light bulbs give adequate light. Plant roots should have oxygen available to keep them alive. Healthy roots (which are white) are responsible for the uptake of all nutrients for the Bok Choy plant. If the roots die, it is impossible for the Bok Choy plant to survive, even if the plant growth requirements are met. Air circulation around plant leaves is important since it mixes the air and allows the plant to draw out the carbon dioxide essential to carry on photosynthesis. Air circulation helps prevent fungal diseases caused by moist, stagnant conditions. Indoor units often have a small fan to circulate the air.

Nutrient pH for growing hydroponic Bok Choy

pH levels of your nutrient solution must be 6.0-7.0. The optimal ideal number is right in the middle 6.3-6.5 but maintaining an exact number is near to impossible as the pH is guaranteed to float around somewhat in any hydroponic solution. A pH level below 5 or above 7 will lead to nutrient uptake and deficiency issues.

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Water solution for growing hydroponic Bok Choy

Use straight water for germination and the first few days following sprouting. By the 3rd or 4th day following the plants sprouting, use a half-strength nutrient solution for about a week before graduating to full strength solution. It is an excellent idea to be a tad cynical and keep in mind that nutrient manufacturers are in business to sell a product and as a rule of thumb will generally recommend more nutrients than you need. Flushing your solution periodically is essential to prevent plant damage via Salt Build Up and other issues.

Aeration for growing hydroponic Bok Choy

Deep Water Culture, in particular, wants adequate oxygenation of the submerged root zone. Floating beds, NFT system, drip, and similar systems also demand oxygenation of the solution, but at a lower ratio to yield optimal or even acceptable results.

A good way to simply monitor the oxygen levels and health of the roots is a visual inspection. The roots must be bright white, thick and fuzzy with multiple root fibers. Scrawny browning roots that simply detach from the plant are a sign of an anaerobic oxygen-deprived plant.

Light requirements for growing hydroponic Bok Choy

Bok Choy needs 6 to 7 hours of light daily. Grown naturally it is a cool-season and excessive light such as that provided by the full sun has been known to cause stress.

Fluorescent Lights, though not the best choice, will work. Due to their low heat emission and soft light intensity, fluorescent grow lights are effective for growing hydroponic Bok Choy. Some of the newer LED lightings are suitable. LED emits a lot less heat than other grow lights which make them appropriate for confined grow rooms and crops such as Bok Choy.

There are multiple varieties of Bok Choy such as Hearting and nonhearting, red-leafed variations and even albino. Growing Conditions vary somewhat with different cultivars but so long as you remain with the general parameters and diligently maintain the plant’s basic requirements.

Bok Choy growing in bucket hydroponics

Bok Choy plants started from seed (Botanical Interests). Moistened with dilute fertilizer solution such as 1 mL (1/5 tsp) Dyna-Gro Liquid Grow per gallon of tap water.

Seeds germinated and transferred to grow room, receiving 3 hours sunlight plus 5 hours LED grow-light per day.

To give plants more light located plants directly under a fluorescent light (2-ft. T8 bulb, 17W, 6500k) for 14 to 16 hours per day.  Plants are only 1 to 2 inches away from the light.

Installed Bok Choy plants into a 3.5-gallon bucket.  Hydroponic solution composed of 3.5 gal tap water, 7 g Master Blend 4-18-38, 7 g calcium nitrate, 3.5 g magnesium sulfate, 0.7 mL Dyna-Gro Pro-TeKt, 3.5 mL pH level Down.  N-P-K (in ppm) ratio will be 103-41-168.  And the pH level will be 6.0.  Bok Choy Plants moved to an indoor grow room, receiving 8 hours LED grow light per day.

At this point, the lower plant leaves are turning yellow and falling off at about the same rate that new leaves are forming, so it is time to harvest these plants entirely. Then plants harvested.

Hydroponic system advantages for growing Bok Choy

  • Using only 10% of the water used on field-grown crops results in great water savings and herbicides are eliminated.
  • Plants growing hydroponically need 20% less space than plants grown in soil. This means you can produce more plants in a defined space or can grow plants in small spaces where it would not be practical to grow soil-based plants.
  • Hydroponic Plants can grow with just 5 to 10% of the water that’s needed when growing with soil. This is of enormous advantage in areas with scarce water resources and is a major environmental benefit of hydroponic cultivation.
  • Hydroponic environments give total control over the climate. You can adjust the temperature, light intensity and duration, and even composition of air, all by what’s essential for optimal growth.
  • Many plants can be produced twice as fast in a well managed hydroponic system.
  • Decreasing the time between harvest and consumption increases the nutritional value of the end product.

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  1. Hi!
    Would like to know the EC reading of your nutrient water for growing bok choy. I am interested to grow them in kratky method.
    Thank you


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