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Hydroponic Vegetable Gardening: Sowing seed in spring hydroponically is the first step for success


Growing plants in a greenhouse environment can rewarding as well as challenging. There’s a whole new set of rules to learn about light exposure, pest problems, and starting seeds. Growing vegetables in a hydroponic unit can make the learning curve steeper.

But once you get the hang of hydroponic gardening, it’s really worth the extra effort. After you get accustomed to adjusting the pH and regularly attending to your system, the plants will grow and flourish in a way that soil-based plants do not. If you’re growing vegetables or herbs, look for a higher output in not only quantity but also quality. Properly grown hydroponic plants are specifically provided with everything they need to thrive, unlike typical soil-grown plants.

Growing plants in a hydroponic system for the first time can present some unexpected challenges. If you’re coming from an environment where you’ve always gardened in soil, get ready for some new rules.

Hydroponic Seed Starting

Starting seeds destined for hydroponic systems involves more than just sticking the seed in soil and waiting for it germinate. Starting seeds requires a day or two of preparation. First, buy some rockwool cubes from your favorite hydroponic supplier. You will need to select what seeds to grow. Beginners may want to start with plants such as herbs, tomatoes, or peppers. Once you have the rockwool cubes, fill a gallon container with water. Use a pH test kit to get an accurate pH reading. If the reading is over 5.5, you will need to add some “pH down.” If it’s lower than 5.5, you’ll need to add some “pH up.” When adding the dilute acid or alkali solutions, go slowly. You don’t want to add too much at once. For example, if the pH of your water is between 6.0 and 6.5, begin with 1/8 of a teaspoon of pH down. If you find that it isn’t enough, add another 1/8 of a teaspoon and so on until you get the correct reading.

Now that you have the 5.5 pH water ready, put the rockwool cubes into a waterproof container. Pour the water into the container with the rockwool cubes. Make sure the cubes are completely immersed in the water. Let them soak for 24 hours. This is important. Rockwool is naturally alkaline. Soaking the cubes will bring the pH up to a more neutral reading. After the rockwool has soaked for 24 hours, the seeds can be sown directly in the pre-punched holes in the tops of the rockwool cubes. Plant two to three seeds per cube. Once the seeds have germinated and grown a bit, remove all but the strongest seedling from each cube. Place the planted cubes in a flat. Fill the flat to a depth of approximately one-fifth of the cube with pH adjusted water. Gentle bottom heat of 75–80°F can help promote faster germination and seedling growth. During this stage, check the pH daily. It should be remain at 5.5 throughout the germination process.

Preparing The Seedlings For The Hydroponic Unit

After the seedling has two sets of true leaves, begin feeding with a mild vegetative solution. To make this solution, take a gallon of water and add in the proper amount of nutrient concentrate according to label’s instructions. Mix it up and wait for a half hour before testing the pH, which should be 6–6.5. If not, follow the previous directions for adjusting the pH. At least every three days, remove the cubes from the container and clean the trays. Then replace the cubes and add fresh, dilute vegetative nutrient solution. Continue this process throughout the germination and seedling stage. It’s important to check the pH every time you use the solution. When the roots are approximately 1/2 inch long on the outside of the rockwool cube, transplant it into the hydroponic system. Continue to gradually increase the conductivity of the nutrient solution every few days until the desired level for the particular crop being grown is reached. The maximum ratio should be no more than 4 teaspoons per gallon of water.

Within a few weeks you will be harvesting fresh herbs or vegetables from your hydroponic system. You will also be able to grow more in a smaller area than what you could grow using traditional soil based methods.

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