In planning my next plant wall I’ve been testing hydroponic planting medium. In the past I’ve used hydroton but there are currently two issues with this media. Because it’s heavy in iron it eventually trashes the magnetic pump. I replace pumps about once a year. At about $50 a pop that’s not horribly expensive but it is inconvenient. Secondly, it’s no longer available. That makes the inherent equipment-related problems with the media moot.
I bought two bags of a product that was supposed to be a replacement for hydroton. It felt like sandpaper, very garnet/scratchy expanded glass feeling. The pieces were quite large for hydroponic media, didn’t break when whacked with a hammer and very light. Other than the roughness and overly large size, I thought it would work fine. Wrong. The stuff floats. Using it in a flood and drain system allows all the plantings to shift every watering cycle. When working with seeds, the media used to hold the seeds vanishes into the mix. Ugh. When planting cuttings they sink a bit into the mix every cycle eventually drowning. Double ugh.
I reported the failure to the excellent staff at our local hydroponic shop and got a sample of another product to try. It had a light silky clay feel, sank when dropped into water and could be crushed. The product is a little big, roughly 2-3 times the size of the hydroton beads.
PH is one of the most important items to monitor in a hydroponic system. I’m not a fan of chemicals and like to handle this as naturally as possible which makes the ph of the media very important. With that in mind I crushed a piece of the new media and tested the ph. It tested lower than I expected at 6.0 which means it’s not inert. Because our water has a very low ph which I moderate with oyster shell, I’m keeping an eye on my test system. Time will tell.
The larger of the upper biofilter tanks is doing really well, though the water hyacinth has not bloomed this year and I’m holding no hope that it will. The triangular water reed has nearly tripled in size even after removing half the original plant last spring to give to Mindy. Jill? Can I restock you when I cut this back in the fall?
This year this larger filter tank is loaded with hydroton which provides shelter for the roots. The water bean, hyacinths and reeds are mega happy, sans blooming.
The smaller tank is also filled with hydroton and has last year’s penny royal which amazingly enough, wintered over due in part to the tank being made of closed cell foam (insulative), containing hydroton (insulative) and filled with standing water (insulative).
Because the maple tree and the triangular reed are sheltering the smaller biofilter tank from the sun the penny royal is growing much more slowly, which is a plus. Last year it was horribly root bound it grew so fast. I cut out most of it and thew it away, then took the remaining bit and cut it in half to give to Mindy.
I like the fairy moss as a fill-in between the larger plants. It helps keep the mosquito population down. Having marigolds growing in a pot on the back frame helps as well. I don’t worry about mosquitoes in the big tank – fish food!
The reed is blooming, though it hasn’t yet peaked to produce the mass of feathery tendrils that will be the end product.
It’s still too cold to put out any of the biofilter plants I’ve tried to winter over but it is time to get the tanks in and circulating. This upper tank is foam. I got it at a year end sale two years ago for $10, a great buy.
Last year I used a tee-less fitting and a piece of rubber hose for the upper tank outlet. All last summer I had issues with the upper tank overflowing due to a too small outlet with penny royal root blocking the flow. I’m hoping I’ve solved some of that with this year’s setup.
I pulled the tee-less connector and inserted a tapering vacuum cleaner wand extension pipe into the hole. After determining I would get a good seal, I pulled it out, trimmed it accordingly and reinserted it into the hole. No sealant was required to give a good water tight fit.
This change allows better outlet flow and the mean level inside the tank is lower decreasing the chance of overflow.
What you can’t see (I’ll drop the water level and get a snapshot before I put the plants in) is the 3″ PVC pipe that keeps the hydroton out of the outlet and inside the tank. The pipe is one foot long with a 45° angled end. This angle fits over the outlet and is fastened to the tank with a 2½” screw. The other end of the pipe is a straight cut which is covered with a piece of 30% sun shade cloth. The length of the pipe has saw kerfs to increase the ability of water to enter the pipe.
This is my new setup, sans the second bucket. I am waiting on tee-less connectors to add the second bucket to the dump tank (existing bucket). I’ll use a short piece of 1½” plastic pipe near the bottom of the buckets to connect them. The two buckets, connected together, will give me the volume I need to fill both beds in a single dump.
Here’s the list of parts.
2 five gallon buckets – mine used to contain pickles and were obtained from a local deli.
black tubing running from the pump to the bucket (visible in the top picture as the black loop to the right of the bucket and in the bottom picture).
100 gallon Rubbermaid stock tank (buried to first step in the tank side).
2 mortar mixing trays (the 8″ deep ones).
miscellaneous scrap lumber – none of this lumber was purchased new. I’ve got 4×4 for the four legs (mix of pressure treated and cedar – it’s what I had), 2×6 for the between post supports and 2×4 for the top plate on which the tray rims rest. The bucket rests on a notched 3×4 and a notched 2×4 held up by 2×8 scraps screwed to the tray frame.
a handful of 3″ decking screws
1 toilet flush valve.
1 16 oz plastic coke bottle (flush valve counter-weight).
black tubing to feed flush valve counter-weight bottle (visible in the second picture – connects to a piece of aluminum tubing which inserts through the bottom of the coke bottle.
miscellaneous hardware including a collection of stainless nuts and washers to act as the flush valve weight (offsets the weight of the plastic bottle so the flush valve flap closes completely).
Plumbing parts – some 2″, some 1½”.
Tee-less connectors to gang the buckets together. I never order enough tee-less connectors. They are the first connector I reach for when I have to fasten pipe to pipe or insert pipe into something. I could have replaced the 2″ tee with a tee-less connector for less than a quarter of the price of purchasing a 2″ tee.
It took me an afternoon to take apart the old single-bed stand (I needed to reuse the legs and some of the shorter lumber) and another afternoon to construct the new two-bed stand. You cannot see it from the picture, but there is a 2×6 that supports the center of the beds underneath going from left to right.
It took another afternoon to get the new bucket and flush assembly put together and get the tray flood plumbing set up.
I still need another 100 liters of hydroton. It should only take another 50 liters (1 bag) of hydroton to fill the beds, but I want to increase the size of the gutter for my plant wall so want some extra to ensure I have enough. Until I get the additional hydroton, I’ll let the beds cycle and build the nitrite/nitrate eating bacteria colony.
Yesterday I rebuilt my aquaponic system to accommodate an additional grow bed. The single tray I used last year was just not enough. I have switched out the gravel I used last year for hydroton (expanded clay balls) so (theoretically) the beds will be light enough to move inside when the weather grows too cold to sustain growing. A single bed filled with gravel would require four muscle men, a pygmy goat and some special equipment. That so won’t work for portable beds. With hydroton I should be able to lift the bed onto a rolling cart for transport indoors.
Now that I’ve got two beds to flood, last year’s system won’t work as is. Two beds means at least twice the water volume. I will gang together two 5-gallon buckets to make up the required flush volume. By ganging buckets together using a short length of 1½ pipe and tee-less connectors, I can supply the volume for both beds using my existing fill and drain system bucket.
So far I’ve got one tray filled and water cycling through but I have more to do before I’m ready to consider planting. I need to cut new piping for the drain system. I want the system to flash-fill the beds so I don’t have to rely on an auto-siphon for drainage. That reduces the complexity of the system and reduces the parts needed to get additional beds attached to the system.
The tank’s water temperature is still below 55° [brrr] but if I’m going to get a head start on the season, I need to get my beds functioning mechanically now. To get the beds up to temperature a little more quickly, I’m thinking of installing a solar water heating system for the tank. We’ll see if I manage to get it done before the tank gets up to temp.
I’ve gotten four meals of lettuce out of my growbed so far. I don’t have a lot of lettuce in the bed . . . I should have a lot more. I’m supplementing with store bought lettuce.
I found a place to get hydroton in Olympia. It was max expensive, $40 a bag when the going rate is closer to $28. I bought two bags. That should be enough to fill both growbeds with a bit left over.
I pulled the gravel out of the wall gutter and replaced it with hydroton. I also trimmed the heck out of a bunch of plants in the grow wall to allow some slower growing things a little bit of daylight. I put some of the trimmings in the gutter along with a couple of sprouting grapefruit seeds.
The orchid in the wall is not doing well. I don’t know if it will recover or not. Time will tell. I should have moved it ages ago.
I long ago faced my addiction to plants and decided it was not a bad thing.