25th of February. Seedlings.

In my last post I started growing hydroponic indoors cherry tomatoes. This is the second of a series on this journey.

water farm

I am using a General Hydroponics WaterFarm just like the one in this picture. It moves up the water with an air pump, using a clever system that pushes up the nutrient solution using air bubbles. This way there is little risk of pump clogging because no dirty water goes through the pump. It also has the pot directly over the reservoir, so no pipes are needed: the water drains directly into the deposit. Simple and functional; I would definitely recommend it. I see only one drawback: it is difficult to have direct access to the reservoir, because you need to move the pot. You definitely don’t want to do it when the plants start getting bigger. Luckily I am monitoring the pH and conductivity with a Nanny: I do not need to access the reservoir because the sensors are constantly in the water. To change the nutrient solution you pour it through the plastic tube that shows the water level. To add fresh solution, you just pour it on the growing pot. The first time draw a line with a marker on the plastic tube just below the level of the bottom of the pot. You know that your deposit is full at this level.

 

For the substrate I chose arlite (expanded clay pebbles).

Expanded clay

Expanded clay

It is a great substrate for several reasons. The main one is that it lowers the risk of rotten roots (which happen due to low oxygen in the nutrient solution). The arlite retains almost no water, but aerates it very well. It can also be recycled almost infinitely: you just have to clean the roots and disinfect it before starting the next culture. Many commercial arlites need to be pH adjusted before using it for the first time, so I washed the material in my bath tub and then put it in acidified water (pH 5.5) for 24 hours. I later learned that it was not enough; I should have left it submerged for at least a week.

first leaves2nd of march. The little plants in their jiffies are doing well. One week after sprouting, they started producing their first real leaves (the first leaves you see are formed from the seed, not “grown”, so they are not “real leaves”) I found very handy to use a small syringe for watering the jiffies. This way you can pour the water delicately, avoiding to harm the plants with a too strong spurt of water.

The camera just gets crazy when I try to take a picture under the LED’s light. There are several problems: the reflective surface of the grow box will always burn certain areas, the high contrast confuses the autofocus and the best of all: the LEDs are blue and red. They have no green because plants don’t use much of it: they reflect it (that is why leaves are green) So, what happens when you illuminate something green with no green light? I can tell that they camouflage pretty well. If you like photography, please, tell me how to take good pictures under these conditions 😉

first leaves LED

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