Principles of Hydroponics

What is hydroponics?

Hydroponics is the process of growing plants in a growing medium like sand, gravel, or liquid, with added nutrients but without soil.

How does it work?

Generally: Seeds are placed in nutrient rich medium, this medium is then “put into the system” or placed under LED lighting and watered many times daily with nutrient rich water, which creates the perfect conditions for plant growth. The system waters the plants by pumping nutrient filled water from a large reservoir through the different parts.

Specifically: Seeds are placed in a growing medium (that has been soaked in nutrient water), the growing medium is chosen based on what they have previously grown well in. The seed and medium are then placed in the “dark stage” of the farm where there is no lighting. The medium is watered daily and once these seeds begin sprouting, they are moved to the “germinating” section of the farm where they are introduced to lighting. When the sprouts grow large enough they are “transplanted” into the different hydroponic growing systems (NFT, flood and drain, deep water culture) to become fully mature plants.

Why is it so efficient?

Hydroponics is so efficient because it: saves space (can be stacked vertically); saves water (recirculates the nutrient water many times); allows for no weeding (no soil, no weeds); has less pests (no need to use toxic pesticides); can grow all year round (since the environment is controlled, you can create the perfect growing environment year round).

What are the easiest most appropriate crops to grow?

  • Leafy greens (arugula, lettuce, watercress, kale…)
  • Vegetables (tomatoes, cucumbers, peppers…)
  • Herbs (mint, basil, fennel…)

Describe briefly the types of indoor lighting.

  • Fluorescent lights- give off a cool blue light which is ideal for seedlings and cuttings. Fluorescent lights provide a wide angle of light, and emit low levels of heat, which creates good conditions for the first stages of a plants lifecycle.
  • LED lights– these lights initially are expensive, yet are highly energy efficient, and they emit less heat than traditional bulbs, so they are good for very small growing spaces where bulbs have to be close to the plants. LED lights can be bought that emit different spectrums of light which will help to produce optimum efficiency in the different stages of a plant’s lifecycle.

Describe the difference between growing herbs versus fruit and flowers.

Herbs – grow quickly, are hardy, no pollination needed, use regular nutrients …

Fruit and flowers – grow slower, are more delicate, must be pollinated by hand, grow better with special nutrient called Bloom …

What are the challenges of hydroponic systems?

Lighting – choosing the right lighting for your system is difficult; making sure that no one unplugs the lights accidentally; making sure they are on a correct timer so as to be efficient …

Watering – very rarely can you over water, but not watering enough at the initial planting stage can make the early stages of plant life a struggle; if you’re using a flood and drain technique with a thin growing medium, over watering (flooding) can occur (to fix this one can add multiple trays to raise the growing medium) …

Nutrients and PH – the nutrient level and PH level must be checked daily and always be watched carefully, as this is an extremely important aspect of the hydroponic system.

Environment – you are responsible for creating the ideal environment for growth in your grow room, may need to take regular measurements of the temperature, humidity, CO2 levels and use fans to create airflow.

Pests – indoor growing has fewer opportunities for pests, but it is well known that they will always get in, and using proper non-toxic methods to remove them is necessary.

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