Hydroponics Guide: How to Grow Carrots Hydroponically

Trying to learn how to grow carrots in hydroponic systems? Even though carrots are root vegetables, they can still be grown well in hydroponic systems, where no soil is used. They are also one of the most commonly sold vegetables in the world and an important source of vitamins A and C. 

Like all hydroponically grown plants, the utmost care and attention must be given to your hydroponic carrots to maintain optimal growth conditions, such as growing medium, light, and nutrients. This article will give you tips and instructions on setting up a good hydroponics system for carrots. 

Basic conditions of hydroponics systems

The supply of water, nutrients, and oxygen are the three most essential aspects of maintaining a hydroponic system. Tap water may be used, although you are advised to leave the water overnight – this allows it to adjust to room temperature and to dechlorinate. In this way, you’ll avoid letting your plants go into shock due to temperature changes. 

In hydroponic systems, it is crucial to supply oxygen to the roots so that nutrient absorption can occur. As such, an ideal system would be one where the carrots are not submerged directly in standing water. If your crops need to be grown in water, ensure that you have an air pump to supply oxygen within the nutrient solution.

Finally, to provide an appropriate supply of nutrients for carrot crops – use a nutrient solution that has a strength of 1120 – 1400 ppm, with a pH of 6.3. For germinating or young seedlings, use a weaker solution slightly above half the strength, and gradually increase the solution strength as the plants mature.

Since carrots are root vegetables, they require a generous amount of space to grow healthily. If there is overcrowding, the carrot crops might split apart, become deformed, or even entwine around each other. The container holding the crops must be filled with media to a depth of at least one foot (for larger types of carrots, you may have to increase this depth slightly.) This is to avoid letting them grow sideways. Finally, never place your carrot crops in standing water, as root vegetables will rot when in prolonged contact with water. 

Choosing the right system and grow media for carrots

Some appropriate hydroponic systems for carrot crops would be the ebb and flow system, wick system, as well as the drip system. Additionally, the carrot crops ought to be placed in a growth medium that is loose enough for some movement to occur – this allows the roots to push through the soil as the crop grows. 

Perlite is one of the best growing media for carrots, and those that are 0.6mm in size often result in the highest crop yields. You may also mix in vermiculite to prevent water retention, with moisture drawn up from the bottom by the perlite, while retaining sufficient oxygen in the mixture. For this medium, add one cup of vermiculite for every three cups of perlite added. 

Other suitable alternatives are clay pebbles or coco noir. While the former can be more expensive, it can be used for aquaponics systems and is also more friendly to the environment. Coco noir has become more popular amongst hydroponics enthusiasts, due to their ability to be reused and give healthy crop yields. This medium has undergone chemical treatment to prevent pathogen growth, indicating that there will be chemical residues that might affect plant growth. 

Setting up your hydroponic system

  1. You will first begin by creating a hydroponic potting mixture. Mix in a half portion of sand, followed by a quarter portion of perlite and peat moss each. Add water to the mixture, until the peat moss has absorbed sufficient water. 
  2. Add the potting mix into a pot, and water it till it begins draining out. This will allow the mix to sink into the pot. 
  3. Push the carrot seeds about half an inch into the mix, before covering and pressing them gently on the surface. For the seeds to germinate, ensure the mixture is at a temperature of 60 – 65°F. 
  4. To make your nutrient solution, stir in 2 cups of dry complete fertilizer into a gallon of room temperature, dechlorinated water. Next, dilute the nutrient concentrate by adding two tablespoons of it to another gallon of water. 
  5. Every morning, water your seeds with a warm, diluted solution. Water them till the solution drains out, and save that amount for the next watering round.
  6. Carrots require light for 12 to 16 hours each day. Use grow lights if your area doesn’t receive enough sunlight, and time the lights to be on for the required duration Maintain an air temperature of 60 – 65°F. This is important to produce a crop yield that doesn’t taste too strong. 
  7. Taking an eight-gallon plastic storage bin, drill holes of three to four inches on each side, three inches from the bottom. Ensure the holes are at an equal position on all sides.
  8. Place the bin in an outdoor area that is warm and receives plenty of sunlight. Add perlite till it reaches a depth of 12 inches. This is sufficient depth for most types of carrots, though some may require more than 12 inches. 
  9. Add water to the perlite surface and add the carrot seeds, spreading them about half an inch from each other. Once the seeds have sprouted to a two-inch height, remove the weaker plants, and spread the remaining about three inches apart. 
  10. Once the carrots have grown significantly, fill the bottom of the bin with nutrient solution. The drainage holes will drain out any excess solution, so do this step in an area where cleanup is possible.
  11. For two to three times a day, spray nutrient solution lightly onto the carrot crops, enough to dampen the surface of the perlite. This will ensure your carrots receive sufficient moisture. If the air is humid, you may reduce the number of times to spray the crops. 
  12. Once the carrot heads have grown to half an inch in diameter, they are ready for harvesting. If you intend to grow baby carrots, you may harvest them when they are smaller instead. Tip: Pull the carrots straight up, so you don’t tear the leaves off the roots.

Most kinds of carrots will take about 70 days to grow fully. Often, however, the time taken for the crops to mature depends on their surrounding conditions. The best way to verify this is to refer to the estimated growth duration on the seed packet and to wait till the carrot has reached an inch in diameter.

Useful tips

  • If you’re using a concentrated nutrient solution, follow the instructions on the packet.
  • If you’re making your nutrient solution, add one teaspoon of Epsom salts, two teaspoons of fertilizer, and micronutrients per gallon of water. 
  • Maintain the nutrient solution at no higher than three inches deep to avoid wetting your crops for extended periods. 
  • Never introduce carrots from an outdoor garden into a hydroponic system, as this might bring in pests and diseases.  
  • For pest control, stick to natural methods. 

Kratky hydroponics method

Some people have successfully grown carrots using the Kratky method. This method involves placing a carrot seed in a piece of Rockwool, before letting it sit in a diluted nutrient solution. Air stones, water pumps, and electricity are not needed. While it is a convenient alternative, note, however, that this method poses a risk of rotting since root vegetables cannot tolerate prolonged submersion in water. 

Growing carrots in a hydroponic system will require lots of care in maintaining the right growth conditions. But with the right mixture of nutrients and grow media, as well as good lighting, temperature, and a spacious set-up for healthy crop growth, you may be well on your way to enjoying a bountiful harvest of carrots. 


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