Light-6-7 Hrs. Daily Solution pH: 6.0 to 7.0 PPM - 1700-2000
Bok Choy, Bok Choi, Pak Choy, Pak choi. Oh boy what a Joy Chinese Cabbage to grow and enjoy. Bok Choy, like many Brassicas can be grown hydroponically very successfully. It is a rapidly maturing crop that can be harvested roughly 30 days from germination. If executed correctly you can actually get 3 harvests from one set of bok choy roots.
There are a number of Bok Choy varietes. Green stemmed, red leaf variations, as well as many that have the familiar white stem.
pH range 6.0-7.0 for optimal results
EC - 2.5-3.0
Temperatures 50 F – 70 degress F Maximum
High Temperatures can destroy the crop
Aeration of Solution and Good air flow essential
6-7 hours of light daily
Grown in soil Bok choy fares well under cool conditions, temperatures of 50 to 70 degrees Farenheit but survives in lower temperatures. High temperatures have been known to cause bok choy to prematurely bolt to seed . Once it bolts to seed the leaves are very low quality and in many cases fit only for the compost heap.
The same requirements apply to hydroponically grown bok choy. The difference relative to temperature in hydroponically grown bok choy is the water temperatures which will also affect the amount of oxygen the water is capable of retaining. Higher reservoir temperatures will impede oxygenation.
It is advisable that you keep the solution slightly lower than the air temperature. Where the air temps can be held at 50-70 F , the water temperature should not exceed 65 F at most. See: Hydroponic Temperature. from the drop down menu on the upper left of this page..
pH levels of your nutrient solution should 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 below 5 or above 7 will lead to nutrient uptake and deficiency issues.
Water / Solution
Use straight water [pH balanced is preferable] for germination and the first few days following sprouting. Avoid Hard Water - See: Hydroponic Water Quality. By the 3rd or 4th day following the plants sprouting, use only a half-strength nutrient solution for about a week before graduating to full strength solution. It is a good 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 usually recommend more nutrient than you actually need.
Flushing your solution periodically is necessary to prevent plant damage via Salt Build Up and other issues.
Studies have demonstrated that aeration of the hydroponic solution produces the best results for bok choy and in many cases is absolutely essential. Aeration methods vary a tad depending on the hydroponic grow system employed. Deep Water Culture in particular requires adequate oxygenation of the submerged root zone. Floating beds, NFT, drip and similar systems also demand oxygenation of the solution, but at a lower ratio in order to yield optimal or even acceptable results.
One study on hydroponic bok choy showed that 'Dry weights were nearly double for those plants in aerated treatments compared to those in a non-aerated treatments' See: Yield of Brassica in Hydroponic Greenhouse Production
A good way to easily monitor the oxygen levels and health of the roots is a visual inspection. The roots should be bright white, thick and fuzzy with multiple root fibers. Scrawny browning roots that easily detach from the plant are a sign of an anerobic oxygen deprived plant.
Light requirements of Bok Choy
Bok Choy needs 6-7 hours of light daily. Grown naturally it is a cool season crop and excessive light such as that provided by full sun has been known to cause stress..
Fluorescent Lights, although not the best choice, will work. Due to their low heat emission and soft light intensity, fluorescent grow lights are effective for growing bok choy. Some of the newer LED lighting is also suitable. LED emits a lot less heat than other grow lights which makes them suitable for confined grow rooms and crops such as Bok Choy. T5 grow lights have been used by some commercial operations and will work well in a small scale grow room as well. See: Grow Lights
There are multiple varieties of Bok Choy / Chinese Cabbage. Hearting and non hearting, red leafed variations and even albino. Growing Conditions vary somewhat with various cultivars but so long as you remain with the general parameters and diligently maintain the plants basic requirements - all should be well.