Gardeners and horticulturalists are used to getting grimy. They root around in the soil, applying fertilizers and pesticides. They plant, divide and re-plant.
They do all this for the rewards of producing beautiful and nutritious plants to view and eat. But what if you could gain those values without coming into contact with any soil at all?
That’s what hydroponics is all about.
Hydroponics is the science and practice of growing plants without using soil. Water is the most common medium used instead. There are more technically accurate definitions, to be sure. But for the home gardener, hobbyist and occasional teacher that’s what it comes down to.
But how is such a thing even possible? Don’t plants need soil for nutrition, heat, support, water and all the other things they need to grow and reproduce? Not necessarily.
Plants definitely do need water. But they needn’t get it from the soil, even though that’s one of the most common methods. Even in nature, some plants grow in sand, gravel or even on the surface or underneath a body of water.
Plants need a certain amount of energy, in the form of sunlight and/or heat from their surroundings. But soil warmed by sunlight isn’t the only way to get that. Direct sunlight still works on leaves, the same way it does for plants in soil. Leaving the upper part of a plant exposed to sunlight supported by a string atop a container will allow vital photosynthesis to occur. As with nearly anything in botany, there are exceptions. Some plants survive and reproduce with no light, though they still need some energy to drive biochemical reactions.
Most plants that interest the home gardener or hobbyist do require physical support. Planting them in soil is one common and effective way to achieve that. That’s one of the reasons roots spread and stems are wind resistant. If they hadn’t evolved that way, those types of plant wouldn’t be here to discuss. But artificial aids, such as strings on supports, ice cream sticks glued to the top of a glass and dozens of other methods will work quite well.
One of the most important elements for a plant is without question proper nutrients. Nitrogen, phosphorus, potassium and a host of trace elements (zinc, copper, iron and others) are essential to plant growth. Absorbing those elements from the surrounding soil is, of course, one usual way of obtaining them. But, here again, nutrients can be fed to plants in a number of ways.
Immersing the roots in a container of water that is periodically fed a liquid nutrient solution is one popular technique. There are others. Some hydroponically grown plants are housed in an enclosure that retains moisture well. The roots are then sprayed often with a mister that douses the roots with a nutrient solution. This crosses into the gray area known as aeroponics.
Hydroponics can be used to grow a wide variety of plants: strawberries, tomatoes, lettuce and many non-fruit or vegetable plants, such as orchids. The list is long. Thousands of species can thrive without soil, provided they’re cared for properly. That effort can be fun and instructive. It can also produce beautiful or nutritious plants without many of the drawbacks of soil-grown plants.