What is Hydroponics?
Do It Yourself
Growing Media
Plant Foods
Starting Formula
Formula Analysis
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Operating Your System
pH for the Gardener
F.A.Q.
Hydroponic Links
Buffer solutions and pH meter. See Tip #4, below.
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Bok Choy ready to harvest. See Tip #9 below.
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Bok Choy after harvest. See Tip #9 below.
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Pickling Gherkins half grown.
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One week later ... Ready for the table.
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Juvenile Cylindra Beetroot up close. See Tip #9, below.
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The Wharfie's hook used as a plow. See Tip #11, below.
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Juvenile Cos luttuce. See Tip #9, below.
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Tip #1.
If the outlet from your nutrient tank to the pump is at the bottom of the tank, you may have a vortex form when the water reaches a low level in the tank. The vortex is merely air getting into the pump, and not many pumps work when full of air bubbles. As a stopgap measure, a piece of angle iron laid over the outlet hole will kill the vortex.
A more permanent solution is to make a mushroom shaped dome/filter. This is made from two pieces of copper sheet about 100 mm in diameter, one of which is domed and the other drilled with many holes, plus a big hole for the "stem". Mount one on top of the other and silver solder together around the rim. Select a piece of copper tube about 50 mm long, that will fit into your tank outlet hole, like the stem of a mushroom, and pass it through the bottom copper plate and solder it into position. Use PVC solvent cement to glue a circle of fiberglass flyscreen on to the underside plate; this will keep leaves out of your pump. If the tube is a loose fit in the outlet hole, squeeze it a bit to make it oval, then jam it in.
Tip #2If you set up your system with more than one pipe module, you will almost certainly have uneven flow of nutrient to each module.
The solution to this problem is to make up one choke for each "U" tube. A choke is a round, stepped, brass button. The smaller step is the same diameter as the inside of the "U" tube and the larger step is the same diameter as the outside of the "U" tube ... like a coin sitting on a larger coin. A hole is drilled through the centre. There is no magical formula to determine the size of the hole, but start small (say 1/8 inch), and if too small, use the next sized drill up. Do not be afraid to silver solder the hole up if it is too large, and re-drill a smaller hole.
To use the choke, pull the hose off the "U" tube and fit the button inside the end of the tube ... if it is too loose, squeeze the tube a bit. Then push the hose supplying the pipe module back over the end of the "U" tube. Swap the choke buttons around if necessary to get a reasonably even flow to each pipe module.
Tip #3To make provision for wet weather, arrange your return pipe to the nutrient tank to be disconnected or diverted to drain when it rains heavily. If it is not diverted, rain water will fill your nutrient tank to overflowing and dilute the contents.
Tip #4
By all means, purchase a pocket type pH meter for testing the pH of your nutrient on a daily basis. There are a few different types on the market and they are good. At the same time, purchase 500 mL each of pH 4 and pH 7 buffer solutions, and read the directions on how to calibrate your pH meter with these solutions. Calibrate your pH meter weekly.
Tip #5
The Author has used conductivity meters for a number of years with mixed results. As a result he does not recommend their use. If you follow the timetable below, you will not need a Conductivity Meter.
Tip #6
Timetable for adding nutrient solution, pH testing and cleaning out.
On day one, fill the tank to 160 Litres (or whatever volume you decide you need), and add one lot of nutrient solution (Solutions #1 to #5 poured one at a time into a plastic bucket of water, then added to the nutrient tank). After adding the nutrient solutions, check and adjust your pH. Aim for pH = 6.4 and adjust down with dilute Sulphuric Acid.
On days two to six, top up your tank to the mark with tap water, and check and adjust your pH. (Spent nutrient generally goes up in pH, i.e., becomes more alkaline, so it needs to be lowered with dilute Sulphuric Acid).
On day seven, add one more lot of nutrient solution, top up with water if needed, then check and adjust your pH.
On days eight to thirteen, top up your tank to the mark with tap water, and check and adjust your pH.
On day fourteen, add one more lot of nutrient solution, top up with water if needed, then check and adjust your pH.
On days fifteen to twenty, top up your tank to the mark with tap water, and check and adjust your pH.
On day twenty one, drain your nutrient tank and use the spent nutrient on the lawn or other gardens. Now fill your nutrient tank with tap water (no nutrient solution, yet) and pump it up to the pipe modules and let it run back down and water the lawn or other gardens with it. This step is important as it removes unwanted salts from the growing beds.
Now, refill the nutrient tank with tap water and add one lot of nutrient solution .... and start all over again.
Do it this way, and you will not need a Conductivity Meter, however, you will need a pH meter.
Tip #7You may choose to grow your own seedlings or purchase them from your local nursery. To keep your growing beds clean, it is a good idea to wash the growing medium off the seedling roots before planting in the beds. Do not wash plant roots in the laundry; it will take time to clean up the mess. Instead, three quarters fill a small bucket or plastic jug with water, then dunk the plant roots in one at a time and jiggle up and down like you would a tea bag, until the roots look reasonably clean. Then, using a knife blade, dig a hole in the coarse sand and pop the plant in and fill the sand around the roots. Now swirl the bucket full of dirty water and spread it on the lawn. Rinse the bucket out and throw the rinsings on the lawn as well. Finished!
Tip #8
Mixed planting and plant spacing. As soon as one plant comes out for the table, another can be planted in the same spot immediately. If you just pulled a cabbage up, you can plant a lettuce, or whatever you like in its place. One pipe module will hold 15 plants, provided they do not spread out too much, i.e., five plants per cut-out.
Tip #9
To get real economy from your hydroponic garden, try to grow vegetables that are not freely available at your local supermarket, or those that are expensive. The Author has given up growing sugarloaf cabbages (easily the best tasting cabbage) because the local supermarket sells them fairly cheaply.
However, fancy lettuce such as Oak Leaf (both green and brown) and Cos (used in Caesar Salads) are available from the local supermarket, and the price is fancy as well, so the Author grows his own from seedlings purchased at a local garden shop.
Other vegetables you may wish to try are Cucumber (Pickling Gherkin), Shallots, Snow Peas and Chinese greens such as Cabbage Michihilli (with prickly leaves), Tatsoi, Bok Choy, Baby Bok Choy and a few other that have yet to be identified ... but they taste good. A Japanese variety called "Senposai" also grows well, but has a stronger taste than the Chinese greens. When harvesting Chinese greens, just take off the larger leaves with a small vegetable knife ... there is still plenty of growth left on the plant. During its lifetime, a Bok Choy plant will produce well over 40 leaves, on the average.
The Pickling Gherkin is supposed to be picked when it is about the size of a man's thumb (so it suggests by looking at the seed packet. Please see the photos on the previous page.), but the Author lets them grow to about 150 mm long by 60 mm diameter .... and they are crisp and taste very good. These pickling gherkins have to be grown from seed as garden shops do not stock them as seedlings.
A variety of beetroot known as "Cylindra" grows well in Brisbane. It grows to over 200 mm in length, but is not available in the shops. It cooks well, and when the ends are taken off, every slice is nearly the same diameter. They have to be grown from crowns (seed pods). A photo of the seed packet is on the previous page.
Tomatoes can be grown with this fertilizer, but you will need a bigger growing tub as the root ball is generally too big for a 160 mm pipe. The Author grows tomatoes in two separate concrete tubs connected to the same system. In Brisbane, the best tomato to grow hydroponically is a variety called "Grosse Lisse". It has a very good taste, but bruises easily, which is why it is not available from the local supermarkets. The seedlings are readily available from garden shops. Also available from garden shops is the Tommy Toe tomato; an heirloom tomato which is about 35mm across and weighs about 22 grams. Please see the two photos on the next page (F.A.Q.)
Baby carrots will also grow well with the tomatoes ... the pipe modules are generally too shallow for carrot roots. Carrot seeds can be sowed straight into the sand and covered lightly.
Tip #10Algae can be a problem in the growing beds. Where you have nutrient solution and sunlight, you will have algae. If you keep the sand level high compared to the overflow drain in the water box at the end of the pipe module, you may minimise algal growth. If the algae is thick enough to form a bed, it can be picked out and dumped. If it is not so thick, it can be stirred into the sand and washed out between pump-ups.
Tip #11
Residual roots. Generally, lettuce, cabbages and Chinese greens take most of their roots with them when they are pulled out of the sand. Tomatoes tend to leave a few roots behind, and cucumbers are notorious for leaving many roots behind. The Author solves this problem with a hook like the type wharfies (longshoremen to US visitors) used to lift bags of wheat. Bend one up from 6 mm steel rod, with a hook about 75 mm diameter at one end and a handle at the other. Sharpen the hook end and use that as a plow to lift residual roots out, and to flatten the sand bed around plants. Please see the second photo from the bottom, on the left for this hook-like plow.
Tip #12
Looking after your pH meter. The correct method for periodically calibrating your pH meter should have been supplied upon its purchase. Various methods of storing the pocket type pH meter are around, but only one works. It is to place two drops of your pH 7 buffer solution (green) inside the cap and stand the pH meter upright in a glass tumbler. Do not put wet cotton-wool inside the cap as it forms algae on the electrode and the wick. Algae can be removed by using a toothbrush very carefully.
Tip #13
Keeping aphids off Chinese Greens. Many Chinese Greens are members of the cabbage family and aphids love them. The Author has tried Pyrethrum to keep aphids away, but does not recommend it as it burns the leaves and the plants take a week to recover. A far better method is to use a Tabasco Sauce spray.
Method to make Tabasco Sauce spray.
Find a clean trigger pack spray bottle and bend the syphon tube forward so that it sucks up product when the spray bottle is tilted forward. Fill the bottle with tap water, then squeeze out 2 mL of water, then add two drops of dishwash concentrate, then add five drops of Tabasco Sauce. Screw the trigger pack pump on, then shake the bottle and it is ready for use.
Using Tabasco Sauce spray.
Spray the leaves, paying attention to the underside of each leaf as this is where aphids congregate. The spray is quite safe on the hands, but be sure to wash your hands after use. Spray the leaves straight after harvest or the next day, while there are few leaves left to spray. Your plants should look like the third photo down on the left hand side, which shows Bok Choy after harvest and ready to spray. Check for aphids two days later and spray the survivors. The withholding period is not an issue as you will not be picking more leaves for at least five to seven days. The Author recommends spraying each time after the weekly harvest to keep aphids away. This stuff really works!
The next page shows how to operate your hydroponic system.