Planting Advice

Sowing and Growing Sans Soil

You will raise most of the plants for your classroom hydroponic garden from seed, but you can start houseplants and many herbs for cuttings of mature plants. If you have a simple system without pumps or other forms of aeration, your best bets are the following:

If you have a more sophisticated active or commercial system, you might also try these crops:

You can start seeds in cotton, cubes of rockwool, peat plugs, perlite, or sand. After planting seeds, check regularly to make sure seeds remain moist, but are not water logged or moldy. If they are too wet, there may not be enough air for seeds to germinate properly. Some seeds, like beans and corn, will germinate in just a few days. Some others, such as tomato, bell pepper, and herbs may take as long as two weeks until they appear. If you do not see any sign of life after two weeks, it is best to replant the seeds.

After the true leaves form and a seedling is from one to several inches tall, you can transplant it into your system. Transplanting a seedling can be very stressful for a plant. Gently and carefully remove the plant, taking care not to damage the roots. A seedling, when transplanted into a bigger growing unit, is stressed at first. Some hydroponic gardeners recommend starting with half-strength nutrient solution, or initially spraying the leaves with nutrient solution rather than spraying or submerging roots, to minimize stress.

Growing From Cuttings

Houseplants such as coleus, tradescantia, heartleaf philodendron, pothos, and geranium grow quite well from cuttings. Rockwool cubes soaked in a 25 percent nutrient solution are nice for starting cuttings. You can also use moist perlite or sand. Cuttings root more quickly if they're covered with a plastic dome or misted regularly to maintain a humid environment.

A Few Plant Care Tips

As with plants grown in soil, your hydroponic unit seedlings and cuttings require ongoing care. Here are a few general suggestions:

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