Hydroponic Gardening FAQ

General
What is hydroponic gardening?
How old is hydroponic gardening?
Is hydroponic gardening easy?
Is hydroponic gardening legal?
Why should I use hydroponic gardening?
What are the advantages of hydroponic versus soil grown plants?
When can I start growing using hydroponic gardening?
What types of plants can I grow with hydroponic gardening?
Where can I set up a hydroponic garden?
Do hydroponic gardens really get better yields in less time?
Does hydroponic garden produce flavor compare to produce from my outdoor, organic garden?
Do hydroponic gardens require the use of pesticides?

System Types
What are the different types of hydroponics systems?
How do I determine which hydroponic gardening system is right for me?

Lighting
What is the difference between cheaper and more expensive grow lights?
Can I use regular lighting/lamps as my grow lights?
How do I determine which lighting system is right for me?

Advanced Nutrients
Why is pH important?
How do you test and adjust pH?
How often should I check the pH?
How often should I change my nutrient solution?
What should I do if I run out of advanced nutrients and can’t get any more for a few days?

Plant Problems
What is the best growing medium?
What causes the leaves of my plant to curl up?
What causes the leaves of my plant to curl down?
What causes the lower leaves on my plant to turn brown?
What causes mold on the grow medium or root rot in my plants?

General

What is hydroponic gardening?
Hydroponic gardening is the method of growing plants in a soilless medium (sand, gravel, rockwool, etc), using water to transport advanced nutrients to plant roots. A soilless growing medium that provides the root system good oxygen exchange, moisture retention, and drainage allowing the root ball direct access to nutrients. Hydroponic gardening results in 30-50% greater yield and much faster growth rates than most other types of gardening methods.

How old is hydroponic gardening?
The science of hydroponics is as ancient as the pyramids.The Pharaohs of Egypt enjoyed fruits and vegetables grown hydroponically. One of the Seven Wonders of the Ancient World, The Hanging Gardens of Babylon, is believed to be a hydroponic garden. Scientists have conducted research in hydroponics for over 400 years in an attempt to advance basic formulas to further the study of plant nutrition and optimal harvestNear the beginning of the 1930’s, Professor W. F. Gericke saw commercial potential in Jean Boussingault’s techniques and began to use them to grow vegetables, flowers, and other types of plants. Since then, hydroponically grown vegetables have been very important in America’s history. Check out The History of Hydroponics Infographic to take the 10,000 ft view of hydroponic evolution.

Is hydroponic gardening easy?
There are a number of different hydroponics methods each with varying degrees of difficulty from very easy to more advanced.  The ease of hydroponics also varies with the type of crop being grown.  Smaller plants and vegetables are easier to grow than larger crops due to size and weight considerations.  While leafy green plants and vegetables are much easier to grow than flowering or fruiting types of plants due to the amount of light power that is required for fruiting and flowering.

Is hydroponic gardening illegal?
Absolutely not. Nothing could be further from the truth. Statistics show that only a tiny percentage of hydroponic gardens are used to grow illegal substances. A large number of plants and vegetables do very well in hydroponic gardening environments. In fact, Canada and Holland are using hydroponics to grow food on a large scale.

Why should I use hydroponic gardening?
Hydroponic gardening systems can be an excellent hobby and provide hours of fun and enjoyment, but for many hydroponic gardening enthusiasts, the real enjoyment begins with eating fresh fruits and vegetables grown using a home hydroponic garden. It takes a little effort and a few bucks to set up a hydroponic garden and start growing fresh food.

What are the advantages of hydroponic versus soil grown plants?
The main advantage of hydroponic gardening versus traditional soil gardening is the most obvious answer…the fact that hydroponic gardening systems do not use soil. This means nutrient uptake is delivered more precisely and with minimal effort on the part of the plant. As a result, hydroponically grown produce is typically larger, more flavorful, and more nutritious than similar produce grown in soil. Indoor hydroponic gardening also means a controlled environment minimizing pests and eliminating the need for toxic herbicides and pesticides and also allowing for year-round crop production. Hydroponic gardening also saves costs because soil preparation, insecticides, fungicides, and crop loss due to drought and ground flooding have largely been removed from the growing equation.

When can I start growing using hydroponic gardening?
Hydroponic gardening means you can grow fresh fruits and vegetables, year-round, with minimal effort. If your hydroponic garden is indoors, in a climate controlled environment, you can basically grow what you want when you want, with respect your resources (time, space, money, etc). However, with an indoor hydroponic gardening setup you’ll need to control the artificial light, temperature, and humidity. With a little time and experience, you can grow cool and/or warm season crops year-round…one of the true benefits of hydroponic gardening.

What types of plants can I grow with hydroponic gardening?
Your choice of hydroponic gardening system(s) will depend heavily on three main factors including your budget, the size of your grow area, and what you are growing. Think small at first — broccoli, beans, lettuce, spinach, snow peas, sweet peppers, tomatoes, and cucumbers. Herbs are also perfect for hydroponic gardens!

What NOT to grow…

Root vegetables like potatoes and turnips…also, although plants like corn, zucchini, summer squash, and melons can be grown in a hydroponic garden they are space hogs and are not practical for smaller hydroponic gardening systems.

Where can I set up a hydroponic garden?
One of the major advantages to hydroponic gardening is the ability to literally grow anywhere…outdoors… indoors… a closet or dark basement.

Although hydroponics is as easy to use outdoors under the sun as it is indoors; one major advantage to gardening indoors under grow lights is that you control the seasons.

Do hydroponic gardens really get better yields in less time?
Yes. Plants receiving all the nutrients they need, tend to be healthier, faster growing and generally more productive.

Does hydroponic garden produce flavor compare to produce from my outdoor, organic garden?
Absolutely! Hydroponically grown produce is typically larger, more flavorful, and more nutritious than similar produce grown in soil.

Do hydroponic gardens require the use of pesticides?
The need for pesticides should be greatly reduced because a strong healthy plant is much less susceptible to attack than a weaker plant. Also, soil-borne pests will be totally eliminated but even in an indoor environment, intruders still find their way in, catching a ride on your person or sneaking through tiny crevices. Monitor any garden carefully so you can catch problem insects when they first appear and your need for toxic products will be minimal.

System Types

What are the different types of hydroponics systems?

There are six types of hydroponics systems:

  • Deep Water Culture (DWC) – The oldest hydroponic gardening system, and one of the simplest, a platform of planters simply floats in the nutrient reservoir while the roots of the plants dangle in the solution. An air pump is introduced into the system to oxygenate the solution. If you are a beginner, this is an easy and inexpensive way to get started.
  • Aeroponic – This variation of hydroponics is more technical, but very effective. The plant roots are continuously sprayed with a vapor-mist solution and are not anchored on any medium, exposing them to air all of the time. When done properly, this method can create large, quick-growing plants and lots of fruit.
  • Ebb and Flow (Flood and Drain) – A growth tray over a nutrient container, and a pump is used to flood the tray(s) with the advanced nutrient solution. The advanced nutrients that aren’t absorbed by the roots are drained into the reservoir and recycled.
  • Drip System – Drip systems are probably the most widely used type of hydroponic gardening system in the world. Operation is simple, a timer controls a submersed pump. The timer turns the pump on and an advanced nutrient solution is dripped directly onto each individual plant by a small drip line.
  • Nutrient Film – The roots of the plants are suspended in a continuous flowing “film” of advanced nutrient solution; a pump sends this stream of solution into one end of the grow channel, running the length of the channel(s) and emptying it into the reservoir the opposite end of the grow channel. This method is great at nourishing roots but is also recognized as extremely technical and difficult to setup.drip nutrient solution onto each individual plant.
  • Wick – This is another very simple method, and no pump is required. A wick (such as an oil lamp wick or candle wick) simply draws the advanced nutrient solution from the reservoir to the growth tray, where the plant roots absorb the solution. This more passive method is low-maintenance, but it can often over-soak the roots, resulting to a smaller yield.

How do I determine which hydroponic gardening system is right for me?
There are many different hydroponic systems available and it is important that you choose a system that is not only going to meet your needs but also be compatible with your growing area. In general, we recommend that novices choose an Ebb and Flow or a Top Feed/Drip System. These systems are great for beginners because they are not too complicated and they will still produce very good results. A few examples of these are the Ebb and Flow, or a Waterfarm Kit. Aeroponic and Nutrient Film Technique (NFT) Systems are usually only recommended for intermediate and advanced growers. These systems require much more experience and general “know how” to successfully operate. Also, because aeroponic and NFT systems use little or no growing medium, you could be in big trouble if a pump fails or the power goes out for a prolonged period of time. Growing in these types of systems can be likened to driving a racecar – you’ll get to the finish line faster than normal but if you have an accident the consequences can be devastating.

The next factor that you will have to consider is the type of plant that you are growing. Certain systems will be better suited for some plants more than others. Smaller varieties of tomatoes, basil, and certain types of lettuce are very well suited to Ebb and Flow or Drip Systems. Larger plants would work very well in Waterfarm kits or BGH Bucket Systems. Lettuce and strawberries grow exceptionally well in NFT systems. Lastly, aeroponic systems can be used with most small vegetable and flower varieties.

Finally, you will want to consider what type of system is going to work best with your growing area. You may be working with as large an area as an entire greenhouse or as small an area as a closet. It is important to consider which systems will best fit into your area. Just remember not to cram too many plants into a given area. A few healthy plants will yield more than several plants that are overcrowded. Overcrowded plants will shade each other causing them to stretch, and the lack of airflow between the leaves will hinder CO2 movement across the leaves. They will also be at a higher risk of being infected by molds and mildews. You might be able to 16 heads of lettuce or basil plants in a 2’ x 4’ area, but don’t try this with something larger like tomatoes or cucumbers.

 

Lighting

What is the difference between cheaper and more expensive grow lights?
More often than not the main difference between high-end lights bulbs and cheaper ones is just the reflector.  High-end reflectors are designed to create more of a spread for both its light output and heat while budget reflectors typically don’t do as good of a job at dispersing light and heat.

Can I use regular lighting/lamps as my grow lights?
Related Information: How to Choose a Grow Light and Grow Light Comparison

Grow lights are just lights used for growing plants. A grow light can be as simple as an incandescent light bulb that fits in a standard socket, a fluorescent or a High Intensity Discharge (HID) system.

Incandescent lamps are the least expensive and cost about $5 for a good 150 watt grow bulb. You can get one of these lamps from a hardware store or large nursery. If you need a nice looking fixture that can get a bit more expensive. A lamp like this will keep a small house plant growing.

Fluorescent lamps work great for starting seeds or cuttings. The 4 foot size is the most common for gardening. One fixture with 2 lamps in it can cover 2, 10×20 inch trays and get your seedlings ready for transplant. Fluorescent lamps need a ballast to operate; it’s almost always built-in to the fixture. The 2 lamp “shop light” fixtures available at the hardware store will cost you about $10. You’ll find a wide range of lamps to choose from, try some cool whites, there inexpensive and work well.

High Intensity Discharge lamps are for serious growing. They are very bright and very efficient. One 1000 watt HID lamp can produce the same amount of light as fifty 40 watt fluorescent lamps. All that power in one fixture! HID systems can be divided into a few categories, High-Pressure Sodium, Metal Halide, Low-Pressure Sodium and Mercury Vapor. The only ones useful for gardening are High-Pressure Sodium (HPS or “Sodium”) and Metal Halide (MH or “Halide”). The most commonly used sizes are 400 and 1000 watt. The 400 can supply enough light for a growing area of about 16 square feet or a 4 x 4 garden. The 1000 watt fixture can cover an area of about 7 x 7. For fast growth, figure about 25 watts of HID light per square foot.

Halide lights emit a blue-white color of light, good for leafy growth. Sodium lights emit a yellow-orange color, good for flowering plants. If you’re planning on getting only one light, a halide is probably the best choice. If you already have some fluorescents, a sodium may be a better choice. A sodium running with fluorescents in the same area will make the best combination of light spectrum, better than just a halide.

How do I determine which lighting system is right for me?
Read how How to Select a Grow Light

Advanced Nutrients

Why is pH important?
Growing plants hydroponically requires a very specific pH range in order for optimal growth and nutrient absorption. If the pH of your nutrient solution is outside the required range your plants won’t get the necessary nutrients they need to grow.

How do you test and adjust pH?
The best way to measure your pH is to purchase a digital pH meter.  These range from about $10 – $50 depending on how fancy you want to get.  While these meters are extremely accurate they do need to be calibrated to ensure accurate readings.  An alternative, low-cost option, is to use pH strips which are pretty foolproof and don’t require calibration. With whatever method you choose it is important to let your water sit for at least 12 hours in order for any chlorine present in your water to evaporate.

If your pH is above 6.5 or below 5.5 you can use a pH Up or pH Down solution to adjust accordingly.

How often should I check the pH?
It’s normal for the pH of your nutrient solution to fluctuate on a daily basis.  Checking and adjusting your pH level once every week or every couple of days should be more than enough.

How often should I change my nutrient solution?
Every week to two weeks is recommended.  In between full changes you can top off your reservoir simply using pH balanced water.  The more often you change your solution the better as this will ensure your plants are always getting the proper amount of nutrients and that your solution is at the proper pH.  Another alternative is to wait until you’ve topped off 50% of your reservoir with pH balanced water.

What should I do if I run out of advanced nutrients and can’t get any more for a few days?
Do not just give your plants plain water, as this would be a terrible shock to the plant- not to mention you would be starving your plant if even for only a few days. Buy an all-purpose water-soluble plant food at your local garden center. If you can, measure the EC or ppm after mixing the solution, to make sure you are giving the same level of plant food as before. Your plants should continue to grow, until you can buy your regular plant food.

Plant Problems

What is the best growing medium?
There is no clear cut answer to this questions. Different mediums work better for different situations and different crops.

We use Rockwool by Grodan, which holds a tremendous amount of water and offers a buffer against drying in the case of electrical outages or pump failures. Rockwool will maintain a 60/40 water to air ratio even when completely saturated, which makes for extremely healthy root growth.

What causes the leaves of my plant to curl up?
If your leaves are curling up it may be a sign that your plants are trying to reduce their surface area in an attempt to retain water. Two possible reasons may be either your lights are too close and are frying your tender plants or your fan may be blowing too strongly and drying out your plants.  Try moving your lights a little further away and redirecting your fan so it’s not blowing directly at your plants.

What causes the leaves of my plant to curl down?
If your leaves are curling down it may be a sign that your nutrient solution is too strong.

What causes the lower leaves on my plant to turn brown?
If your plant is lit with a top light this may be an indication that not enough light is reaching the lower levels of your plant. This is completely normal and you shouldn’t be alarmed as the top leaves should capture enough light for your plant to continue to thrive.  If you’d like you can provide supplemental light from the side to ensure your bottom leaves are getting enough light as well.

What causes mold on the grow medium or root rot in my plants?
Overly wet conditions due to watering at night or when dark, or from too many flood cycles.