Hydro culture: Hydroponics for House Plants
By June Angus
In North America, public awareness of hydroponics has grown by leaps and bounds over the last 20 years. The same can’t be said, however, for people’s knowledge of hydro culture, the technique for growing decorative plants and tropicals without soil at home or in indoor public spaces. The story is different in Europe, where hydro culture has been evolving for almost 40 years. In Holland, Germany and Switzerland, one-third to one-half of all indoor house plants and decorative plants in offices and public spaces grow without soil. Experience there shows that most plants which grow indoors in soil, grow well and require less care in hydro culture.
Hydroculture’s popularity comes from its advantages over growing plants in soil:
- No more over watering or under watering – a water-level indicator shows exactly when to water.
- Plants need to be watered less frequently.
- The need to transplant is reduced.
- Plants grow more quickly because the plant uses less energy to grow roots and directs more energy to growing the part of the plant we see and enjoy.
- It’s clean, odorless and non-allergenic great for people with allergies to fungi etc.
- No soil-related diseases or pests.
Every person has a different reason for getting started with hydro culture. In my case, it simplified plant care. My track record with soil-grown plants hadn’t been very good because I regularly forgot to water them.
Hydro culture made watering automatic and even when the reservoir is empty there’s usually moisture left in the expanded clay pellets. As a result, I have some plants that continue to thrive after almost two decades in hydro culture.
A good friend living in Sarnia, Ontario, got into hydro culture in a serious way when she developed severe allergies to the molds found in soil. She was an avid gardener indoors and out and just couldn’t bear our long Canadian winters without any indoor greenery. Hydro culture eliminated the soil and her problems with gardening indoors.
How it works
Hydro culture systems are made up of five basic parts: clay pellets, fertilizer, water level indicator, culture pot insert and outer container.
Clay Pellets: Clay pellets are the growing medium of choice to take the place of soil. They are porous, retain moisture, and transfer moisture to the plant’s roots by capillary action. Plants settle their roots to their required moisture level so plants with different watering requirements can grow together.
Fertilizer: In hydro culture, plants have a regular feeding schedule that eliminates guesswork involved in feeding soil grown plants. The feeding frequency depends on which kind of hydro culture plant food you decide is most convenient. There are two basic choices: A 2-3-2 liquid fertilizer can be added at every watering. (Watering is done from the top. ) Or a slow release nutrient (loose granules or gelled disk) is placed in the bottom of the hydro culture water reservoir every six months. Regular plant foods lack trace mineral elements so are not recommended for hydro culture. However, hydro culture nutrients do work extremely well for soil-grown plants.
Water level indicator: Most water level indicators resemble a thermometer and discreetly protrude from the container. As water is added, the marker in the indicator rises. As the water is used up the marker falls. When it has reached its bottom level, it’s time to water. Add to the optimum or half mark. Only fill to the maximum level under special circumstances, for instance, an absence off three or four weeks, a very dry house, or if large plants run out of water in less than a week.
Culture pot inserts: The hydro culture insert is a very special culture pot which provides an oasis for plants. This is the heart of the system and is available on the market in many sizes ranging from 7cm (2 3/4 in.) to 35cm (14 in.). Culture pots are made of plastic and designed with openings in the bottom. When the indicator reaches the optimum mark, the openings are under water. As the water level goes down, air circulates in. When water is added again, the rising water level forces trapped air up through the clay pellets bringing oxygen to the plant’s roots.
Outer container: The final part of the hydro culture system is an outer container – a closed water reservoir – that can be any size color or shape. In fact any closed planter can be converted to hydro culture. Metal containers, such as brass or copper, should be lined with a closed plastic container before converting to hydro culture.
In the 70s and 80s, several companies in the United States and Canada sold hydro culture products through direct sales at in-home demonstrations. Today, hydro culture is available from specialty indoor gardening or hydroponics stores.
Which plants to grow?
Most indoor plants – from a thirsty tropical to the desert-loving cactus – grow well in hydro culture. Small plants or rooted cuttings transplant more easily than larger plants. Taller Dracaena, Philodendron and Yucca species transplant more easily. For best results, use only healthy plants.
Flowering plants are more fragile to transplant, although there’s no problem with African Violets, Spathiphyllum, Hoya, Succulents, Anthurium or dormant tuberous and bulbous plants. Younger plants that haven’t yet flowered are best.
Getting plants into hydro culture
Rooting cuttings in water, vermiculite or rooting stone is the easiest way. Transplanting soil-grown plants into hydro culture is another alternative. The process is not difficult if you follow these simple instructions.
- Soak the necessary quantity of clay pellets in room-temperature water for a few hours or even overnight.
- Remove the plant and attached root ball from its soil container. Tap lightly on the sides and bottom of the container, or squeeze the sides and the plant will come out easily, especially if the soil is slightly dry.
- Gently crumble off loose soil from around the root ball with your fingers. Be careful not to damage the plant’s main or tap root.
- Rinse off the remaining soil with clear lukewarm water. (Be kind to your plumbing and don’t let excess soil go down your drain.) If the plant has an entangled root ball, let it soak for a few hours.
- Inspect the roots for remaining soil, especially between the larger roots just below the base of the stem. If soil remains, use a soft toothbrush or mushroom brush. Be careful. Don’t scrub! Then rinse the roots again.
- With clean sharp scissors, cut off any dead, rotting or broken roots, and trim approximately one-third off the roots to promote new root growth. For small root systems, just trim the tips.
- Fill clean culture pot insert to one-third with clay pellets. Set the plant onto the pellets and spread out the roots.
- Keep plant at same depth as in soil.
Hold the plant in place and fill the insert with clay pellets. Hydroculture plants have smaller root systems, so choose a container the same size, or one size smaller, than the soil pot.
- Run room temperature water through the pellets to settle the root system and remove any remaining foreign particles. 9. Place the new plant, culture pot and indicator into the outer container, and add room temperature water until the indicator shows half full or optimum. Set the plant in a bright, warm place, away from direct sunlight and drafts.
- Do not add nutrient for about month. Wait until the indicator shows empty before watering. Your plants may be in shock for the first week or so and may wilt or even lose leaves. Don’t worry. They should recover soon. (Shock is common with all transplanting – even for soil.)
If there’s a problem, don’t be afraid to take the system apart, inspect the roots, remove any rotting roots and replant following these directions.
To transplant to a larger hydroculture pot, grasp the stalk lifting the plant out of its old culture pot – roots wrapped around clay pellets and all. Place the plant in its new culture pot and fill the remaining space with clay pellets.
Happy hydroculture gardening!