Can maincrop potatoes grow in soil-less environment?

[GpsFrontier]

Hello kr3t3n,

As I mentioned in my earlier post I plan to grow them using an aeroponic system. The potatoes won't fall off because of weight. The plants roots are quite strong, as well as get bigger and thicker as the tuber (potato) gets bigger. The bigger the potato gets the bigger the root supporting it will be. It's not like a melon or pumpkin that can get over 10 pounds. Even the large baking potatoes only weigh about one pound.

You do need good plant support to keep the whole plant from falling through the opening into the root zone though. Support the main root ball at the base of the stem while allowing the roots to grow through, and support the foliage above as well.

Foggers by themselves simply don't supply nearly enough moisture. The fog always falls to the bottom making it very hard to get even coverage throughout the entire root system. The ultrasonic pads tend to clog (even the Teflon ones can), and foggers have been known to aid fungal growth.

[kr3t3n]

Originally Posted by GpsFrontier

Hello kr3t3n,

As I mentioned in my earlier post I plan to grow them using an aeroponic system. The potatoes won't fall off because of weight. The plants roots are quite strong, as well as get bigger and thicker as the tuber (potato) gets bigger. The bigger the potato gets the bigger the root supporting it will be. It's not like a melon or pumpkin that can get over 10 pounds. Even the large baking potatoes only weigh about one pound.

You do need good plant support to keep the whole plant from falling through the opening into the root zone though. Support the main root ball at the base of the stem while allowing the roots to grow through, and support the foliage above as well.

Foggers by themselves simply don't supply nearly enough moisture. The fog always falls to the bottom making it very hard to get even coverage throughout the entire root system. The ultrasonic pads tend to clog (even the Teflon ones can), and foggers have been known to aid fungal growth.

Thanks very much for the answer and the explanation, good to know! In that case, I guess you would use a low-pressure system with "sprinklers"?

How would you calculate the watering frequency and gaps between?

[GpsFrontier]

Hello kr3t3n,
Yes, it will be a low pressure aeroponic system. Not only is a low pressure system much easier and cheaper to build, but a low pressure system would also produce larger diameter roots, and thus I would think potatoes as well.

How would you calculate the watering frequency and gaps between?

Like always, by plant observation mostly. There are so many variables that the only real way to know if a plant is getting what it needs is by observation. I would probably start with a regular timer that has minimum 15 on/off times, and run it alternately. 15 on, and 15 off. If I felt that was to long between cycles, I would switch to a cycle timer and probably start running it for 5 on, and 5-10 off.

[kr3t3n]

Originally Posted by GpsFrontier

Hello kr3t3n,
Yes, it will be a low pressure aeroponic system. Not only is a low pressure system much easier and cheaper to build, but a low pressure system would also produce larger diameter roots, and thus I would think potatoes as well.



Like always, by plant observation mostly. There are so many variables that the only real way to know if a plant is getting what it needs is by observation. I would probably start with a regular timer that has minimum 15 on/off times, and run it alternately. 15 on, and 15 off. If I felt that was to long between cycles, I would switch to a cycle timer and probably start running it for 5 on, and 5-10 off.

I was thinking that a possible way to avoid the problem with mist falling down is to place the mist maker(s) on the top of the root container. I've tried to make a quick sketch here: http://imgur.com/a/e11Kd

Unfortunately, it is neither the best sketch nor a good photo, apologies if very difficult to understand. I was thinking of making a basin for the mist maker(s) near the top of the container which will overflow and the mist will presumably overflow as well, falling down through the roots. Would you think such a system would work?
In the top drawing I've tried to draw a box which has 4 plants
In the second drawing I've tried to draw where the mist makers basin would be with their positions (I've forgotten to add some padding from the top)
In the bottom one I've tried to make a "close-up" of the mist makers basin.

The only reason I'm looking at mist makers as watering method is because sources on the Internet claim that the roots accept nutrients easily (more naturally) when the drop size is near (if not exact) as what the mist makers produce.

Plants absorb elements most efficiently in the range of about 1-25 micrometers (µm), and though foggers work somewhat differently depending on the manufacturer and model, a fogging system will supply vapor at between 5 and 30 µm.
Source: https://www.maximumyield.com/figurin...gponics/2/1361

Having this in mind, if the mist really covers the roots, shouldn't it produce better growth? Although it would probably make watering frequency very different.

[GpsFrontier]

Hello kr3t3n,
First foggers and misters aren't the same thing. Foggers produce fog, not mist. Fog is dry, mist is wet. Have you ever went outside on a foggy morning? Did you get wet? That's because there is very little actual moisture in fog.

While I'm not scientist, I can tell you that the water droplet size doesn't determine the size of the mineral element molecule. Plants can't absorb nutrients/mineral salts unless they are in their single raw chemical state. That is unless they are a single molecule. If they bond with another molecule, their not usable to the plant regardless what the water droplet size is.

With that said what makes the water droplet size important is aeration. The small water droplet size allows for better aeration and oxygen uptake. Thus the root growth is much smaller and finer. Like millions of small hairs. These tiny hair like roots are much more efficient in absorbing nutrients because their's a lot more surface area to absorb them. This is why I said a low pressure system would be able to grow bigger potatoes. The water droplet size in a low pressure aeroponic system is much bigger than in a high pressure system. Bigger water droplet size means thicker roots. Bigger thicker roots can support bigger potatoes than tiny thin roots will. With the smaller thinner roots you may get more potatoes because there will be more surface area, but the potatoes will be much smaller as well.

P.S.
Even if you had the fog drop down from the top into the container, it will quickly drop all the way to the bottom. The only way to get even coverage is by creating enough fog to constantly fill the entire container. The fog will fall out of the first opening in the container it can as well. Even if you are able to fill the container with fog for even coverage, there still isn't enough moisture in it and you would have to get more moisture to the plant another way.

[kr3t3n]

Originally Posted by GpsFrontier

Hello kr3t3n,
First foggers and misters aren't the same thing. Foggers produce fog, not mist. Fog is dry, mist is wet. Have you ever went outside on a foggy morning? Did you get wet? That's because there is very little actual moisture in fog.

While I'm not scientist, I can tell you that the water droplet size doesn't determine the size of the mineral element molecule. Plants can't absorb nutrients/mineral salts unless they are in their single raw chemical state. That is unless they are a single molecule. If they bond with another molecule, their not usable to the plant regardless what the water droplet size is.

With that said what makes the water droplet size important is aeration. The small water droplet size allows for better aeration and oxygen uptake. Thus the root growth is much smaller and finer. Like millions of small hairs. These tiny hair like roots are much more efficient in absorbing nutrients because their's a lot more surface area to absorb them. This is why I said a low pressure system would be able to grow bigger potatoes. The water droplet size in a low pressure aeroponic system is much bigger than in a high pressure system. Bigger water droplet size means thicker roots. Bigger thicker roots can support bigger potatoes than tiny thin roots will. With the smaller thinner roots you may get more potatoes because there will be more surface area, but the potatoes will be much smaller as well.

P.S.
Even if you had the fog drop down from the top into the container, it will quickly drop all the way to the bottom. The only way to get even coverage is by creating enough fog to constantly fill the entire container. The fog will fall out of the first opening in the container it can as well. Even if you are able to fill the container with fog for even coverage, there still isn't enough moisture in it and you would have to get more moisture to the plant another way.

Thank you very, very much for this reply. It has answered a lot of questions in my head. I hope I'm not irritating you as I find your answers very useful and learn a lot!

Now I completely understand why fog/mist does not help but even harms the intentional growth of potatoes (while it might be very helpful for growing other plants where saturated root growth is desired).

What are your thoughts on using plastic grill (for weight support) under foam for growbed media? Any ideas what would work best?

[GpsFrontier]

Hello kr3t3n,
No your not irritating me at all, that's what forums are for, asking questions and sharing what you know. I can't always reply right away as I am quite busy these days. Sometimes I may even forget to get back to it when I have more time, but I enjoy trying to help people.

I'm not sure I understand what you mean by "using plastic grill (for weight support) under foam for growbed media?" Are you referring to same aeroponic system your planing for potatoes, or another type of system and or plants? Anything that comes in contact with the water/nutrients should be some type of plastic. If it doesn't come in contact with the water/nutrients, then you can use just about any material to support the system with.