How to Grow Carrots in a
Hydroponic System
by Bob Kowal
(Spokane WA)
HOW do you grow carrots in hydroponic gardens? I want to grow some inside and would like to know the best equipment to get started with doing that.
Also, I am writing a book to help teachers teach science easier and would very much like your permission to use the diagram Life Cycle of a Plant in the book. I will reference your site and tell readers to go visit it for the awesome info on hydroponic gardening.
May I have your permission to use the diagram? I love seeing a young man getting involved in science - good luck to you.
Bob Kowal, Simplification of Science
Answer: Bob- you absolutely have my permission to to use any of the images from my site in your book. Now let's talk science!
A hydroponic system supplies plants with three basic things....water, nutrients (in the water), and oxygen (at the root level). Systems can be modified or adjusted to accommodate the growth habits of a particular crop, but these three basic needs must always be met.
Water is easy enough to provide. Most tap water will do, though it is a good idea to let it sit out overnight to de-chlorinate and also to come up to room temperature. This helps prevent damage from temperature shock.
Oxygen at the root level is important because nutrient absorption only occurs in the presence of oxygen. Any hydroponic system in which the plants are NOT grown directly in standing water will automatically provide enough oxygen to the roots. When plants ARE grown directly in standing water, an air bubbler is used to keep lots of oxygen dissolved in the nutrient solution. It is important to note, however, that some plants simply do not like "wet feet". This is one reason it is important to know the growth preferences of your plants before you settle on a particular hydroponic system.
As long as you know how to maintain a nutrient reservoir properly (see how to grow hydro), providing nutrients to your plants is a simple matter of knowing their nutritional requirements. Carrots, for example, prefer a pH of about 6.3 and a nutrient solution strength of 1120-1400 ppm (16-20 CF). It is important to add that they are started out on a weaker solution at first.
Root crops need lots of room to grow. This is especially true with carrots. Carrots need to be "thinned out" in a hydroponic system just as they need to be when grown in soil, and for the same reasons. Over-crowded carrots will fork, grow deformed, and wrap around each other. They also will not grow as large as they should. If the container is not deep enough, the carrots will grow sideways when they hit the bottom. Root crops like potatoes and carrots need a light weight, loose grow medium that is easy to "push out of the way" as they grow. Finally, root crops should not be grown in directly in standing water....they tend to rot when they are kept too wet.
With all of this in mind, there are a couple of good strategies for growing carrots hydroponically. One is to use 12 inch flower pots filled with perlite or a mix of 2 parts perlite to one part vermiculite (to retain the moisture better). These pots can be hand watered from the top two or three times a day, and can also be placed in a container with a half inch of nutrient solution. The perlite tends to draw moisture up from the bottom, but also maintains a lot of oxygen within the medium. This meets the needs of the plants in a simple fashion. The same thing can be accomplished in a more automated form by adding a small water pump, a few drip emitters, and a digital timer.
Another system for gardening carrots and potatoes is very similar to the above, using 32 liter plastic storage totes filled with plain perlite. Several 1/4 inch holes are drilled into the containers 3 inches up from the bottom. This allows 3 inches of nutrient solution to stand in the bottom, which the perlite constantly draws up into the rest of the grow medium. Again, the container can be hand watered from the top a couple times a day to maintain moisture in the top layer, or a drip system can be set up with a small water pump and a timer.
The storage tote system has been used for at least two years with very good results. Once you know the basic requirements of the plants you are growing, it enables you to make changes or improvements to your hydroponic system without fearing bad results.
