To get started with hydroponics at home, you should take an inventory of your goals and budget to begin. For a 48×24 inch ebb and flow (flood and drain) system, Your total cost will be around $600. If you grow potatoes, it will take quire a while to recoup this cost. Basil, however, at $3 for a young, fresh plant for pesto, will probably return your investment in as few as 2 years (6 inch diameter per plant = 8×4 plants in table = 32 plants x $3/plant = $96/harvest / 3 months maturation = $32/month – electricity – more nutrient – seeds = ~$25/month). If you choose to use all organic and can find a buyer, expect a much more lucrative return.
Ebb and Flow Hydroponics Overview
Here a a small diagram of the setup that will be described below.
If you don’t have $600 laying around, you can step into hydroponics more slowly by starting with a deep water culture system or smaller ebb and flow setup. I’ll argue though that planning a setup this size and buying it incrementally will make the most sense. We’ll breakdown the various components here.
Hydroponics Light Source
Starting with the light source makes the most sense. Begin by purchasing the most lumens per square foot that you can afford. Note that will not necessary be the largest fixture. A 2×2 ft fixture that packs in many bulbs is just as good. Direct sunlight is around 9000-10,000 lumens per square foot (or 100,000 lumens/sq meter) so that is our target.
The fixture show above contains 8 T5 bulbs that will produce 40k lumens each or 320K lumens total over an area of approximately 4×2 feet (8 sqft). That makes 40,000 lumens per square foot. After accounting for inefficiency in reflection for light that is initially directed up, light that is lost horizontally, and decreased efficacy of the bulb as it ages, we should still be around the 10k/sqft sunlight equivalent. We’ll ignore wavelengths for now and say that T5 is a good bulb choice because they are cool enough to be very close to the plant canopy.
You can germinate plants with much less light. This amount of light will allow your plants to thrive, bloom, and fruit however. Once you have this set up, try it for a few months on a traditional potted plant and you’ll be sold.
Hydroponic Grow Media and Flood Table
The next large investment in your ebb and flow hydroponics setup will be a flood table, reservoir and grow medium. From the diagram above, hopefully you can get the idea that your reservoir can be just about anything that holds water. I scoped out craigslist for a few months as was able to find a fifty-five gallon aquarium for $50 that holds water just fine.
The flood table will either need to be supported by the reservoir or by some sort of stand. Since the flood table will contain grow media which will displace some of the water, the volume to flood the the flood table will be less (maybe 50% less) that calculated volume. Assuming that the reservoir is covered to minimize evaporation loss, You can begin to estimate the maximal amount of time between filling the reservoir. This is also known as how long you can go on vacation.
A 48 x 24 x 6 flood table is 6912 cubic inches or just under 30 gallons. If we assume 50% displacement but grow media, we’ll need 15 gallons to flood the table. Let us add in 2 gallons of water to keep the pump submerged and the minimum water requirement would be 17 gallons. Since our reservoir is 55 gallons, if we fill it completely, will will have 38 gallons of “extra” water that we will either loose to our plants or evaporation.
Different plants have different needs for water. Lettuce is notoriously good for large scale hydroponics as it sucks a large amount of water. This isn’t to say that you can’t raise hydroponic cactus though. Hydroponics Made Easy claims a young tomato plant will use 300ml-1L of water per day. We would have 96 plants in a full bed or 28.8-96L/day (7.6-25gal/day). So this system probably has between a 1-7 refill period depending on plant type, maturity, and density.
The hydroponic grow media simply serves a means to keep roots moist but not wet (like a sponge. Hydroton is a commercially available clay pellet that is commonly used.
Ebb and Flow Water Pump System
The water pump is the key component of the ebb and flow (flood and drain) hydroponic system. The goal is to have a pump capable of raising an appropriate volume per minute to flood your table relatively quickly but not so fast as to cause erosion of your grow media. The higher your flood table is from the base of your reservoir and the larger your flood table, the larger the pump your need. The larger the pump, the (generally) louder it will be and more electricity it will consume; although nowhere near the consumption of your grow lights.
The water pump will be on a timer to flood your plants several times daily while your grow lights are on.
Plants cannot live on water alone. The nutrients, associated pH solutions, water, and electricity will be the main recurring expenses.
You can put off aeration to the end but you will not want to put this off too long. like your plants, algae will have all the ingredients to grow. Changing your water at regular intervals and keeping your water aerated will help combat this thread.
Remember that air stones will help get more of the gas dissolved into the water so plan on picking up a few air stones. Also, a one-way check valve is a good idea if your pump is not submersible as there is always a chance of backflow of water when the system is turned off.
Aeration, unlike lighting and the water pump can continue 24 hours a day. Make sure that your air outlet are not is the same area as your water pump intake as this will decrease efficiency and life of your water pump.
There are the rough estimates for getting started with a moderate-sized hydroponics system at home. This hydroponics setup will grow, blood, and fruit anything from tropical trees to cactus if you tweak the solutions and times of flooding. Happy harvesting.