In hydro plants are grown in an inert medium such as perlite or pebbles, and a water and nutrient solution provides the plants with all the nutrients they need. This soil-less method of growing was used by the ancient Aztecs to create their floating gardens. It is now used by commercial growers to produce 90% of the flowers and 65% of the fresh fruit and vegetables sold in the U.K, by NASA to feed astronauts on long flights and by polar explorers at long-term camps.

What's the difference between passive and active hydro?
Passive hydro is simply growing without soil. This means that the grower knows how much nutrient the media has started with (none) so that they know how much more to provide to the plant. Active hydro also involves using inert media but plants are placed in an active hydro growing system that automatically pumps water and nutrient from a reservoir, around the plant roots and back into the reservoir. This means that the plant has constant access to everything it needs and water logging or nutrient build-up is prevented because whatever the plant doesn't take is drained away.

Why does active hydro work?
In conventional growing the gardener has to guess or estimate how much water and nutrient is in the soil or pot, so there is a risk of over or under feeding. This is avoided in active hydro and other benefits include:

• Healthier plants - over and under feeding is avoided as the flow of water and nutrient to and from the roots is constant (re-circulating system) or timed (ebb and flood system) and the plants can take as much or as little as they need.
• Quicker growth - all of the plant's energy is focussed on growing upwards. Plants in soil use 50% of their energy to develop deep root systems in order to access water and nutrient and compete with soil.
• Stronger roots - roots have better access to oxygen because the inert medium lets air flow through to the roots and can't become water logged or compacted.
• No pests - no soil means no soil-borne pests or diseases and reduced need to use pesticides.
• Easy maintenance - many hydro system tanks only need to be refilled every few days, or even weeks and growing medium never needs to be replaced.
• Space efficient - high and low water loving plants can share the same pot because the roots are not sitting in a pool of water so don't become water logged. Up to five different plants can be grown in a single one metre long hydro system.
• Odour free.
• Water efficient - water is recirculated and isn't wasted on soil as the plants are placed in an inert growing medium, which doesn't take up any of the water.

So, put simply growing with hydro takes the guesswork out of feeding and watering, meaning that they get exactly what they need, when they need it, so that you get bigger and healthier plants.

If you would like to try this form of gardening go to Greenhouse Sensations for more information.