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Description:

Hydroculture is a method of growing plants without soil. Plants do not need soil but they do require light, air, water and nutrients. Hydroculture allows us to continually give our plants the right amount of water and mineral foods and to properly oxygenate plant roots. It is a proven concept perfected for tropical plants in Switzerland and now in use throughout the world. In Switzerland today nearly half of all ornamental plants in cultivation are grown without soil and the same is true for much of western Europe.

Advantages of Hydroculture:

• No earth - therefore clean, odourless and non-allergic
• Reduces the need to transplant. Nutrient, water and air are provided in proper proportions. The roots don't waste energy searching out these required elements.
• No soil related diseases or pests
• Water level indicator shows you when to water. Watering is done only when the reservoir is nearly empty. Using this method reduces worry on vacations and weekends.
• The growing medium rarely needs to be replaced.
• Plants that may be difficult to grow in our environment, can thrive in hydroculture.
• Plants with high and low water requirements can be potted up in the same container and will flourish side by side.
• Each plant takes up only the moisture and nutrients it requires.
• Chances of plant disease and death are greatly reduced.
• Often plants faster growth.
• Large plants will grow well in small containers.

Preparation/ Planting:

Planters:

Specially designed planters or inserts must be used for hydroculture. They are available in many design styles and sizes. A water level indicator (either a glass window in the reservoir or a freestanding gauge) tells you exactly when it is time to add water - generally every 2 to 3 weeks.

Porous, gravel-like rock is used to hold the plant and absorb water and nutrients from a water reservoir below. Haydite is expanded oil shale mined in Canada. Leca is a man-made clay pellet imported from Europe. Both haydite and leca work equally well.

Fertilizer:

A special hydroculture nutrient plant food must be used. Add liquid hydroponic nutrient every second watering or time-release granules can be added every six months. Follow instructions provided.

Transplanting from soil:

Preferably transplant plants when young as the risk of loss increases with the size of the plant.

1. Water the soil in the pot completely and then remove the plant and its attached rootball.
2. Crumble the loose soil from around the rootball being careful not to damage too many of the fine root hairs.
3. Place the rootball in a pan of room temperature water for 15 minutes and then gently clean the remaining soil from the roots.
4. Gently rinse the roots in clean water or under the tap (always at room temperature).
5. Rinse the haydite or leca and spread two handfuls in the bottom of the planting container.
6. Hold the plant in the container (sitting slightly lower than its normal planting depth) and add sufficient stones to fill the container.
7. When the plant is securely potted, rinse the stones under the tap to remove any excess dust.
8. Put the plant container into its base or outer container and then fill with fresh room temperature water until the level indicator shows the reservoir is full. Do not use plant nutrient for one month.

Your plants will require a few weeks to settle in their new home and the damage caused when you cleaned their roots may result in a few lost leaves. Do not worry, new ones will grow soon.

If you have cuttings that have produced roots, either in water or in a rooting medium, they are ideal for planting in your container. Just follow the directions above, from number 4.

Plant Maintenance:

Always let the water level descend until it is almost empty before refilling. This will allow the air to circulate to all the roots. Then fill with water. Once every 2 to 4 months run lukewarm water through the container to rinse the stones completely.

Hydroponic Systems:

Small home hydroponic systems allow people to grow fresh herbs and salad greens all year round. These crops do fine in a simple absorption hydroponic system - using vermiculite - no pumps or intricate irrigation systems are required. Systems, complete with nutrient, instruction booklet, and vermiculite, retail at modest prices (e.g. $10 to $30 plus lighting -- typically a 1 metre fluorescent fixture with two 'cool-white' tubes on an adjustable stand).

Other vegetables, such as tomatoes, prefer a substrate such as haydite in an active hydroponic system with a simple pump and irrigation system. A basic module retails complete for about $90 and up. The home gardener is advised to use at least six fluorescent tubes (mix 'Grolux' and 'cool-white' tubes).

Cautions/Considerations:

Plants require both micro and macronutrients to survive (16 are considered essential for survival). Proper fertilization is essential. Plants will display deficiency if nutrient requirements are not met (e.g. leaves may be small and light green, or have weak stalks or lower leaves may be lighter than upper leaves when Nitrogen is deficient; dark green foliage, or yellowing between veins on lower leaves, or purple colouration on leaves when Phosphorus is deficient; lower leaves may have a mottled appearance, margins and tips may have dead areas, or leaf margins may be yellow with Potassium deficiency).

References:

• The Toronto Botanical Garden Weston Family Library is an excellent source for horticultural information.
• Douglas, James Sholto. Beginners Guide to Hydroponics (Soilless Cultivation). New York: Viking Penguin Inc. , 1985
• Kenyon, Stewart. Hydroponics for the Home Gardener. Toronto, Canada: Key Porter Books, March, 1992

Factsheets are produced by the Toronto Master Gardeners in association with the Toronto Botanical Garden. They provide introductory information about a broad range of horticultural topics and are intended for personal use and study purposes. Should your gardening group or organization wish to use multiple copies we ask that you inform the Toronto Botanical Garden at info@torontobotanicalgarden.ca.

Date revised: January 8, 2006