
What if Farming Didn’t Need Soil?
Special | 7m 42sVideo has Closed Captions
Farming without soil could help feed the planet as farmland shrinks and the climate changes.
Is this the future of farming? Hydroponics grows plants without soil, and aquaponics adds fish to the mix. Using nutrient-rich water instead of farmland, these methods are gaining traction as sustainable ways to feed a growing population in the face of climate change and less available farmland. Here's how it works.
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SCI NC is a local public television program presented by PBS NC
Sci NC is supported by a generous bequest gift from Dan Carrigan and the Gaia Earth-Balance Endowment through the Gaston Community Foundation.

What if Farming Didn’t Need Soil?
Special | 7m 42sVideo has Closed Captions
Is this the future of farming? Hydroponics grows plants without soil, and aquaponics adds fish to the mix. Using nutrient-rich water instead of farmland, these methods are gaining traction as sustainable ways to feed a growing population in the face of climate change and less available farmland. Here's how it works.
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Learn Moreabout PBS online sponsorship(upbeat music) And really fell in love with the idea of a good process creates a good product.
- Eric Woodall is proud of the crops he grows on his farm and of how he grows them.
Oh, he gets his hands dirty, but he doesn't grow fruits and vegetables using soil.
- I thought, okay, well, here's an opportunity with some new systems that haven't been explored quite as much, but it's a chance to innovate.
It'll be something that's different and exciting and really just trying to solve problems that I saw coming down the road with food security and climate change.
And someone's got to step up and try and fill that void that isn't being filled.
- Woodall is a hydroponics farmer.
- This is a raft.
It's called a beaver raft, lettuce raft.
It's special built to take one inch grudging plugs and then it just grows right down in the water while the roots stretch out and absorb nutrients as it passes on by and air.
- His farm, In Season Aquaponics, sits inside a giant greenhouse in Anger.
12 different varieties of lettuce, along with spinach, kale, and many other vegetables and herbs are produced year round and sold to area restaurants and at farmer's markets.
- We actually sell these lettuce with the roots on.
- And it's just gonna keep going.
The water's moving constantly.
- Constantly moving.
We've got it aerified and of course, lots of nutrients in there and by keeping it moving, we can keep fresh nutrients going from one plant to another.
(upbeat music) - That concept of growing plants exclusively in nutrient-rich water with no soil is what confuses people.
And if you look at how the roots grow into there, they're not actually part of the dirt.
The dirt isn't being absorbed by the plant.
It's growing around those little dirt molecules and searching for water that has been, that has had those nutrients dissolved into it.
- So hydroponics farmers engineer the water to basically power grow crops.
Creating the perfect environment allows farmers to extend the growing season for crops.
Those crops also generally grow faster.
Lettuce grows from seed to harvest in roughly nine to 12 weeks.
- You know, I think the most excited I get about the lettuce is when we take it to market and people literally pick it up and they say, it looks like a bouquet of flowers because it really is a pretty piece of lettuce and you don't see stuff like this at the grocery store every day.
- We can monitor and adjust all of the nutrients so that it's a perfect mix, ideal for growing very quickly and as well as pH.
We can adjust the pH up or down to make sure that those nutrients are actually available to the plant.
Well, as you can see, some of the lettuce we have here is harvest ready.
As we harvest that lettuce, we will actually clean and sanitize the rafts and repopulate them with new transplants and put it right back in the culture.
(gentle music) (water splashing) - Well, we put these little plugs into the holes there and then we press them down so that we get them through far enough and if you can see this.
Does it go extend beyond the end?
- Yeah, that's the plant right there.
- So you get it in there so that that's not enough space to hit the water and so that's the way they keep moist all the time.
- Plants are also matched with the optimal growing system.
While lettuce grows well floating atop free flowing water, kale and spinach grow better with roots in a thin film of flowing water.
- Let me show you here.
We've got basically just an open channel.
They actually call it NFT or nutrient film technique.
By separating this from our lettuce, we're able to increase the concentration of nutrients here too, which these plants prefer a higher concentration than the lettuce.
In any of these systems, you're really limited by the plant that will tolerate the least amount of nutrient concentrations.
- But larger plants, which take longer to grow, would overwhelm hydroponics systems using flowing water.
- Okay, this is a Beto bucket system.
We have these buckets that are special designed to support plants as opposed to the system with the water.
We feed these plants, again, a nutrient rich solution of water about every two hours during the daylight and it just grows in this inner media.
This is called perlite.
It is a rock.
What we like about it is it has a neutral pH and has a lot of airspace so that it has places for nutrients, water and air to grow.
- While hydroponics farmers grow plants in nutrient rich water, some farmers are taking an additional step and turning to aquaponics, which adds fish to the farming mix.
That's right, fish.
There's a tank of striped bass overlooking the greenhouse.
Woodholt wants to move from straight aquaponics, growing plants in nutrient rich water, to hydroponics, raising fish and plants together in a closed system.
- The goal would be to move from a synthetic fertilizer into an organic fertilizer so that we can really achieve the whole purpose of this farm, growing fish and vegetables in a symbiotic environment so that we can be really stingy with water and really stingy about using nutrients to grow lots of food in a small area.
- The challenge is converting the toxins produced by the fish, ammonia and solid waste, into something less toxic that can be used as a fertilizer.
So one of the challenges is that you're, instead of trying to culture just the plant and being able to give it what it needs, you're now trying to culture the fish, give it what it needs and the plant, and give it what it needs at the same time.
And so if that water needs to go through the fish, through the plants and back, and oftentimes again with a microbial, maybe a biofiltration section, then that water has to satisfy all of those creatures.
pH for example, plants tend to prefer a slightly lower pH, fish a slightly higher pH.
So then you're looking at this sweet spot and that's hard.
- And that's why there are many variations of aquaponic and hydroponic farms, but the industry is growing.
- It's always an experiment and you have to be willing to try some different things and see what happens, push the envelope and be a little different.
I think that at the end of the day, this could be something that works out really well for us.
Just need to overcome some challenges to learn.
- Thanks for watching.
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SCI NC is a local public television program presented by PBS NC
Sci NC is supported by a generous bequest gift from Dan Carrigan and the Gaia Earth-Balance Endowment through the Gaston Community Foundation.