Mobile hydroponics vehicle

Question

I had an idea for a group of nomads/travellers who sustain themselves with mobile hydroponics system and whatever they can grow on the move.

How feasible would it be to have a mobile hydroponic farm capable of comfortably sustaining one person that can be mounted on a vehicle of some sort?

From the rough calculations I did, it certainly seems to be doable;

Farmland needed to sustain one person $\approx$ 0.5 hectares or $5000 m^2$.

Hydroponics $\approx$10x more efficient that dirt farming (includes density and no need to lie fallow).

Means roughly $\approx 500 m^2$ of hydroponics, or a square about 25m on a side.

Obviously this is a very rough, back of the envelop calculation, but it certainly seems doable. Even if you'd need a large truck. This only covers food as well - not any other crops you may want to grow to produce fuel/fabric etc etc.

Other concerns:

• Power & Water - hydroponics needs plenty of both - obviously if you're on the move you could use the vehicle as a power supply, or supplement it using solar/wind power.
• Effect of vehicle vibrations on the plants - both normal engine noise and rough terrain. (Would it be possible to somehow utilize the vibrations as part of the hydroponics system?)
• Sunlight - either have to be exposed to the sunlight, or use artificial light sources - which uses more power.
• Weight - All the machinery/water/plants would be very heavy and would affect the performance of the vehicle.
• Mobility - at the end of the day you've got to be able to move, preferably with some off-road capability.

Obviously ship-based hydroponics is feasible, but I was wondering about the possibility of a land-based hydroponics society

Maybe if you has the hydroponics set up in a tiered system on the back of an old semi-trailer?

Bonus Question: Could a mobile hydroponics farm on the back of truck produce enough biofuel to keep itself moving?

Answer 1

Not only is this doable, you can do it now.

https://www.freightfarms.com/product/#lgm-basics

These folks will sell you a hydroponics grow truck exactly as you propose. It looks very cool! I could imagine this would be nice for a modular farm set up that would be easy to expand. It also might be nice for illegal or other high value crops you might want to keep moving, to avoid attention or discovery.

I think you might need a fair bit of water for this. If you were moving a lot thru open deserts you could get one of those 2-trailer trucks like they use in Australia, with one being full of water.

Answer 2

The obvious question I have to ask is about the nutrient base.

Hydroponics don't just need plants and water; the plants themselves need nutrients that they extract (via roots) from the soil normally; in the case of hydroponics, they extract it from the water and the fertiliser has to be in solution within the water for it to work.

The most common form of fertiliser used in industrial farming is known as NPK fertiliser (Nitrogen, Phosphate & Potassium), which comprise the 3 primary building blocks for plant growth. Over time however, you need more trace elements and you also need certain bacteria in the soil in normal plant growth in order for them to thrive. When you get down to it, unless you're growing a single crop and you're set up for it with a LOT of science behind you, hydroponic farming isn't sustainable in the long term. If it was, farmers would have switched to it long ago.

So; you still need access to high quality fertilisers with trace elements, you need key bacteria in your water supply (rendering it non-potable, or non drinkable so you need your own personal supply), you've already mentioned the energy requirements and the issues with mobility.

If you're doing this because you're in a post-apocalyptic world, you're still boned. Hydroponics are not a replacement for soil based solutions without a LOT of supporting infrastructure that just isn't there. If it's a mobility thing (you just can't stay somewhere long enough to grow a crop) you're heavily dependent on trading to survive. Even if you're prepared to use your own fecal matter to supplement the fertilisers, there are issues with that long term and it better only be a single person system.

So; possible? Yes. Practical? No. This isn't a solution that will be sustainable or even healthy over the long term but it might just be enough to make large desert crossings and the like if you had to.

I can imagine these trucks being rented out like camper vans today, where on arrival at the township on the other side, they are resupplied with water, fertiliser, new plants etc. and then rented out to the next person wanting to go back in the opposite direction. THAT might make it doable, but the cost of renting the unit would be very high because of the maintenance that would have to be done on both sides of the journey.