Hydroponic Vegetables

Raised Hydroponic beds made out of Trampoline frames, wood and fiberglass

I am back at work and the rain is showing no signs of abating for at least another week so I am not getting much of a chance to get out into the yard. Nicci and Andrew are coming down on the weekend to help move some rubbish and put some welded gates up but its will probably be too wet to do much else. 

Seedlings

The job that I am really itching to do is get stuck into fiber glassing the raised hydroponic grow beds. When I built the first test bed I only put down one layer of fiberglass and didn't add a gel coat. 

This was my first FG project and it was a bit messy but it has been functional and the bed designs are getting better.

As soon as the weather clears I want to add another reinforcing layer of fiberglass around all of the corners of the boxes and then give them a white gel coating. I trialled using plastic sheeting but it wasn't very practical so I will be redoing all the boxes with a FG water seal.

First experiments in Hydro Greens

The idea of using large raised hydro-beds came to me a couple of years ago when I was trying to find a way of increasing the planting density of leafy green vegetables in one of my existing hydro systems. I was originally planting seeds into the beds and then waiting 4 to 8 weeks for the plants to grow. The problem that I saw was that the bed space was being taken up for that entire period even through it was only the last 20% of the growout time that needed lots of growing space. The other 80% of the time the greens would stay confined to a very small area.

Experiments in whole pot transfer

I tried an experiment where instead of direct sowing the grow-bed gravel, I planted the seeds into pots and then planted the pots into the gravel beds. This worked really well and I trialled different sized pots in an attempt to work out how close I could cluster them together. 

Really small planters did work but the leaves failed to form a thick ball. When I tried a slightly larger pot the results were much better. Drilling some holes in the plastic also helps to let the roots out but this also means you have to be careful when transplanting the pots when a larger growing space is required as you might damage the root structure.

Spare Pots

Specialized Hydro growing pots are naturally well designed for this purpose but were relatively expensive when I looked into them. I was able to get large numbers of standard pots for almost nothing through the dump recycling center in Yeppoon so I chlorinated these and continue to use them as such a lot of of them are needed.

There are 4 large 6 square meter grow-beds in the yard and each bed can hold between 200 and 400 plants. Depending on the type of vegetables that you plant, the grow out time is about 4 to 8 weeks which means that 4 beds can produce enough vegetables to meet the needs of an average to large sized family.

Cabbage Seedlings

The only really serious problem that I have had using this growing method is infestation from cabbage moths. The first experimental planting that I did consisted of 300 Bok Choi plants which fully grew out to large, beautiful vegetables. I came outside the morning after deciding that they were ready to pick and found that the entire lot had been decimated in one night by tiny green caterpillars.

To me the pest problem is a nuisance that can really give you a headache but when I look at this, all I can see is the incredible success that can be made on the path to food self sufficiency if the problems can be ironed out. 

Some people use Dipel on their greens which is very effective and is considered to be an organic pesticide as it is based on the naturally occurring BT bacteria. This is something that I might start using if I haven't been successful at eradicating the caterpillar scourge by next year.

At the moment I am trying exclusion pest netting that I bought from Green Harvest and I am putting in some light traps to control the moths.

Greg R