The aquaponics garden has been running for a little under four weeks now, and I thought I’d give a little update.
My water parameters are a bit of a mixed bag. I am very happy to have measurable nitrate (vial on the far right) levels, as this is evidence that nitrifying bacteria have taken up residence in the system, and is also the form of nitrogen that plants are happiest to use. I am also happy to see nitrite (blue) levels at zero, where they are supposed to be. My ammonia levels fluctuate between zero and something barely detectable. Today it is not zero and I suspect that the nitrifying bacteria have not yet become numerous enough to handle the ammonia load of the fish and their feed in as timely a manner as I would like. I must learn to feed less to prevent this. The big glaring issue with the water is the ph. It has been steady at 8.4 since the beginning and this is well above what is ideal for the plants. Goldfish can tolerate ph levels that high, but it intensifies any ammonia problems, so I have to keep a close eye on that. Plants absorb nutrients at different levels depending on ph, and moderately alkaline water can result in deficiencies of micronutrients. The good news on this front is that the nitrification process is naturally acidifying, so over time this should be less of a problem. I live on a huge slab of limestone rock, which contributes a great deal of hardness to our well water. This has the effect of buffering the ph, which complicates efforts to lower it.
My poor little basil plants from the grocery store, which were so feeble looking when I planted them, have beefed up quite substantially, but a few days ago, their older leaves turned yellow and black. Obviously this is some sort of deficiency, but the new leaves are reasonably green. Of course, for most of their tenure here, the water has been practically nutrient free, so it remains to see what will happen to them.
I planted a lot of seeds, which have germinated marvellously. Planting them involved nothing more than sprinkling seeds over the media and running my hand back and forth across the surface to drop them into the spaces between. Now that most of them are starting to put out their first true leaves, I’m seeing a lot of paleness in the leaves. As the nutrient level of the water improves, I’m hoping the plants will as well.
I started Swiss Chard and a few other things in these little plugs called Rapid Rooters. They are commonly used in hydroponics and promise to provide ideal growing conditions. The chard was doing fine until a couple of days ago when it started falling over. I may pluck one of the plugs out to examine the root system. I fear that chard is sensitive to high ph like its cousin beet, and no doubt the general lack of nutrients has taken a toll.
The stars of the show are the eight goldfish. They have grown noticeably since arriving and appear to be thriving in their new home. As I mentioned in my last post, I hadn’t really intended to keep them as pets, but they are revealing themselves to be interesting creatures and I’ve really enjoyed watching them.
Now that the system is cycled and the plants have grown up a bit, it’s time to start thinking about the final component – worms.