Hydroponic kits are the perfect solution for those that want to grow delicious fresh herbs and vegetables but have a small space or very little time. Once they are set up, hydroponic gardens produce masses of produce from quite a small space and since there is no weeding and no digging, gardening couldn’t be easier.
Growing vegetables hydroponically is not as tricky as it seems and the systems available now lend themselves to small spaces such as a patio or balcony through to a full scale production garden to feed a large family. Although the size of the systems may change, the basics stay the same. A small pump continuously circulates a nutrient rich solution from a reservoir across a bed of growing media in which the seedlings are planted.
This constant circulation of water along with a very low evaporation rate makes growing hydroponically one of the most waterwise methods for gardening. In fact, hydroponic gardens are up to 80% more water efficient than soil based gardening.
All that is required of the hydroponic gardener after the initial set up is to monitor the nutrient level of the water weekly, fill the reservoir as needed and empty and refill it every month or two. In between that, it’s simply a matter of harvesting the produce as well as a little bit of pruning and tidying.
Growing hydroponically has many advantages. There is no soil, no weeds, no digging, no soil-borne diseases and no need to rotate crops. The tanks can be raised to a comfortable level and they produce a huge amount of produce from a relatively small floor space. Hydroponic gardens may even be the best solution for those gardening in areas with poor soil, where space is an issue or perhaps where daily watering and garden maintenance is difficult. With a hydroponic system a gardener can go away on a week’s holiday, or even longer, with no concerns at all.
Almost anything can be grown hydroponically. Leafy greens will be available for harvest in just three weeks and vegetables can be ready for picking in as early as six weeks.
Mushrooms are just about the only common vegetable that can’t be grown hydroponically. Lettuces, Asian greens, spinach, rhubarb and Silverbeet are amazing grown this way and fruiting vegetables such as eggplant, tomatoes, cucumbers and zucchini thrive as there is no risk of them drying out through their growing period. Even corn and melons can be grown hydroponically as can peas, sugar snaps and beans which can be grown up a frame sitting above or around the tank. Although it might seem unlikely, root vegetables such as carrots and beetroot are both massive and delicious when grown in a deeper hydroponic system. The flavour of vegetables grown hydroponically easily surpasses those bought from the supermarket.
SETTING UP A HYDROPONIC SYSTEM
No longer are hydroponic systems the convoluted tangle of pipes and tanks that they once were. Much more attractive and compact systems are now available that can be purchased in a kit making it simple so that all you have to do is ‘just add water’.
Setting these up is quite easy though it is always best to place the tank where it will stay before filing with water as once it is full it will be too heavy to move. Choose a level position that is easy to get to for harvesting and that also gets at least 6 hours sunlight for edible plants and some protection from wind. Tanks can be moved throughout the year to make use of sun traps in winter and areas with afternoon shade in summer.
The small water pump that is included in a hydroponic kit is usually only five watt so uses very little electricity. These can also be run using a small solar panel meaning that they can be placed almost anywhere in the garden. The pump needs to run 24 hours a day so that the water from the reservoir continues to flow through the growing media.
The kit will also include a planting media that gets spread over the upper tray. The purpose of this is simply to give the roots something to anchor themselves into so as to hold the plants up. The media will probably be expanded clay pebbles but other materials such as Perlite, fine gravel, Rockwool or even clean washed sand will also work effectively. The expanded clay and Perlite are both preferable since they can be easily washed and used over and over again. Avoid using vermiculite as it tends to break down and becomes a slushy mess.
It is worth experimenting with the planting media used in the system especially if the hydroponic garden is being used in extreme temperature conditions. Grey gravel warms up more quickly in winter or cooler climates and can push some early season vegetables along quickly where as Rockwool might be more effective in the north where its high water holding capacity might be beneficial.
THE PLANTING STAGE
Hydroponic plants require the same nutrients as those grown in soil; it’s just that it is delivered to them differently. Choosing the right nutrient formulation is much easier now for beginners than it has ever been before. A formula is available specifically for the early stages of growing vegetables and leafy greens and another suits cut flowers and ripening vegetables such as tomatoes, cucumbers and chilli. Ask at any Better Pets and Gardens for the best formulation for your hydroponic garden.
The nutrient is added in solution to the reservoir at regular intervals. This will probably be weekly at the height of the growing season and fortnightly for the rest of the year. Once a month the reservoir is completely drained and filled with fresh water and nutrient solution to ensure that the nutrient level and pH stays constant.
In areas with high rates of evaporation or a salty water supply, the concentration of salts gets quite high after only a week so these systems will benefit from being drained and replenished every week. A plastic tap placed in the base of the reservoir makes this job much easier. Interestingly, most vegetables will tolerate higher salt levels in a hydroponic system than they would in a soil-based garden bed.
Sowing seed to plant into a hydroponic garden is possible but for beginners it is probably best to plant commercially grown seedlings. These simply need the soil gently rinsed off their roots using a bucket of water before planting. If time, letting them sit in a diluted solution of the hydroponic formula for a few hours before planting into the media helps to make the transition from soil to water more effective.
For those that want to try growing from seed, push the top layer of growing media aside to reveal the moist level underneath. Drop the seeds in and re-cover. Sprinkle a little water over the top to assist in germination. Large seeds such as beans and peas can go a little deeper but small seeds such as basil and rocket should be quite shallow although still at a level where they will receive water. Seeds can also be place in Rockwool cubes and then placed into the growing media.
Water cress, Vietnamese mint and other water plants can be grown in the deep end of the system where the water collects before returning to the reservoir.
DEALING WITH PROBLEMS
Just like vegetables grown in the garden, pests can still be a problem but given that hydroponic systems are generally smaller, dealing with these is easy. Aphids may affect buds and new shoots and these can easily be squashed between finger tips. Caterpillars on the leafy greens are obvious from holes in the leaves and can be picked off and discarded. Non-toxic sprays can be used if the numbers of these pests becomes too great.
If the tips of leaves are curling up, the nutrient mix may be too strong. Check that the pump is working and top the tank up only with water so as to dilute the solution. If there is no improvement, drain the tank and replace the water then keep the nutrient level slightly lower.
If the nutrient mix is too weak, the plants will appear yellowish or pale. Add a little more of the nutrient formula just to bring the level up. If this doesn’t help, drain the tank and replace with fresh water.
Generally, hydroponic systems are easy to use and have very few problems that can’t be solved almost immediately. It’s simply a case of being observant and learning the little tell-tale signs that plants always display.
Different herbs and vegetables can be grown together so long as they have similar requirements.
Plants that prefer a low nutrient level:
- Pak choi
Plants that prefer a high nutrient level:
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- Silver Beet
- Sweet Corn
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