I like to grow my own vegetables and greens.
I have done it in my backyard garden and I was blessed to reap the final products most times. I recently found an interesting topic - hydroponics - an art of growing (mostly greens but not limited to it) with nutrient solution instead of soil. In hydroponics, you just replace soil with nutrient solution. Everything else remains the same : sunlight, air, the problem of pests, etc.
Obviously, like any gardening or farming, there are different ways to do it. When it comes to hydroponics, hobbyists use multiple setups - raft system with air pump, pipes setup horizontally in racks (checkout vertical farming), etc.
Apparatus
The most important part of hydroponics system is the food for plants - the nutrient solution (measured for pH and EC). To measure them, I use the following tools:
- HM Digital pH Meter
- HM Digital Electrical Conductivity (EC) Meter
One suggestion before using the tools, read the freaking manual.
My Hydroponics Setup
For all the experiments I will:
- use jiffy plugs throughout the plant lifecycle (from germination to the final stage)
- use a hydroponics raft system - a small tray (10-12 L capacity) with holes for netpots and airpump.
- have outdoor setup under shade. It can withstand rains but cannot guarantee against heavy rains / winds.
- make sure the air pump runs 24 hours everyday. It will be turned off only when measuring the pH and EC of the solution or adding more of the nutrient solution.
- use a two part nutrient solution. It’s just two solutions and doesn’t have different solution pairs for growth and bloom phase.
My First Attempt - Spinach
The initial seedlings stage was super awesome. It took 3 days for most seeds to germinate and have it’s real leaves.
Spinach after 3 days
I transferred it to an open environment but still not under direct sunlight / winds / rain. It was quite sunny and the water in the jiffy plugs dried up few times. I added little amount of water whenever I see the signs of less water.
Spinach after 8 days
The plants growed in good shape and its already been 9 days. I think it’s time to transplant them in nutrient solution before it’s second pair of leaves grow.
Spinach seedlings in netpots
For growth of Spinach, the solution requires pH to be in range 5.5 - 6.5 and EC to be in range 1800 - 2300.
I mixed the concentrated nutrient solution in RO purified water. The EC of the solution was ~50 µS but forgot to measure the pH (which I lately found it to be 6). I mixed around 100 ml of the concentrated solution in 10 litres of water assuming that everything goes as per the manual. But the solution became very acidic (pH ~4). I had to add more water and remove at the same time to make sure the pH is within range and the total solution doesn’t overflow the required amount.
I finally managed to get the pH near around 5. Even though its outside the required range, it was less acidic than before. Meanwhile I forgot the quantity of solution in the setup. ️🤦♂️
Monitoring growth
Here are the following EC and pH readings of the solution and remarks (if any).
| Date | pH | EC (µS) | Temp (C) | Remarks |
|---|---|---|---|---|
| 10 Sept 2020 | 5 | 1105 | - | Had messed up the pH level of solution but still placed the plants in net pots. This is to see if the plants would die if the solution was so acidic. |
| 11 Sept 2020 | 6.8 | 1235 | 25.2 | Looks like there is some serious calibration error. The pH has gone out of range again and will kill the plants (as per my understanding). Anyhow the experiment continues. |
| 12 Sept 2020 13:30 | 6.8 | 1253 | 24.3 | The plants seem normal. Need to bring the pH lower. Poured ~32.5 ml of each concentrated nutrient solution. Testing the solution after an hour, the pH was 6.3 and EC 1823. |
| 13 Sept 2020 12:30 | 6.3 | 1830 | 24.3 | Rodents (I doubt a bandicoot 🐀) had digged cocopeat in 8 netpots and destroyed them. Only 4 survives with few cuts. |
| 16 Sept 2020 08:15 | 6.6 | 1890 | 22.2 | Was sad last few days as I had lost plants but I must keep going. The remaining 4 plants are growing but not fast as those grown normally. To decrease the pH added 20 ml of each concentrated solution. |
| 17 Sept 2020 12:10 | 6.3 | 2286 | 23.9 | - |
| 18 Sept 2020 17:30 | 6.4 | 2364 | 25.4 | The EC of the solution has crossed the required range. I think this is because of dust. Also I added 30 ml of two part solution to decrease pH. The EC has increased the range and I need to look at how it affects the plants. |
| 20 Sept 2020 15:00 | 6.2 | 2971 | 22.7 | Added 20 ml of two part solution to decrease pH. |
| 21 Sept 2020 18:00 | 6.1 | 3335 | 23.5 | Plants show growth. The wind makes the plants grow slantly. |
| 22 Sept 2020 18:30 | 6.1 | 3405 | 23.1 | - |
| 23 Sept 2020 18:00 | 6.2 | 3441 | 24.5 | Saw mosquitoes breeding in the hydroponic solution |
| 24 Sept 2020 18:00 | 6.3 | 3488 | 25.6 | Added 20 ml of two part solution to decrease pH. |
| 25 Sept 2020 18:00 | 6.1 | 3850 | 26.3 | - |
| 26 Sept 2020 18:00 | 6.1 | 3907 | 24.5 | - |
| 27 Sept 2020 18:20 | 6.1 | 4000 | 25.1 | - |
| 28 Sept 2020 18:00 | 6.1 | 4089 | 25.2 | - |
| 29 Sept 2020 18:05 | 6.1 | 4180 | 23.7 | - |
| 30 Sept 2020 18:00 | 6.2 | 4186 | 24.5 | Theres no much change in EC. The solution might have been contaminated with rain water but the pH has increased. Added 10 ml of two part solution to decrease pH. |
| 1 Oct 2020 18:00 | 6.0 | 4396 | 25.1 | As each jiffy plug has 3-5 seedlings, the leaves get tangled. |
| 2 Oct 2020 18:00 | 6.0 | 4466 | 25.8 | The water level has decreased, major factor being evaporation. 3 out of 4 seedlings have their roots protruded through jiffy plugs. |
| 3 Oct 2020 18:00 | 6.1 | 4514 | 24.3 | - |
| 4 Oct 2020 18:00 | 6.1 | 4570 | 24.2 | - |
| 5 Oct 2020 18:00 | 6.1 | 4581 | 25.5 | - |
| 6 Oct 2020 18:00 | 6.1 | 4636 | 26.2 | - |
| 7 Oct 2020 18:00 | 6.2 | 4802 | 26.1 | Added 10 ml of hydroponic solution. |
| 8 Oct 2020 18:00 | 6.1 | 5014 | 26.9 | Added 10 ml of hydroponic solution to further decrease the pH. |
| 9 Oct 2020 18:00 | 6.0 | 5341 | 24.5 | - |
| 10 Oct 2020 18:00 | 6.0 | 5455 | 25.5 | - |
| 11 Oct 2020 19:00 | 6.0 | 5545 | 23.3 | - |
| 12 Oct 2020 18:00 | 6.1 | 5606 | 23.5 | - |
| 13 Oct 2020 18:00 | 6.1 | 5671 | 23.3 | The plants are not growing since few days. Few leaves have shriveled and the stems of many plants are weak. Stopping the experiment. |
What did I learn the hard way?
- Measure the pH and EC of the
- water before mixing concentrated nutrient solution
- solution in raft system after some time. This reduces any errors due to incomplete dissolving of nutrients.
- Make sure there are no rodents around the setup
- Take measurements of pH and EC on same time everyday
- Mosquitoes can breed in the setup. Need to figure out how to prevent it.
What I didn’t like?
- Hydroponics has two major components:
- the nutrient solution (fertilizers) : It takes time to understand if greens grown in a hydroponic setup has some side effects when consumed.
- plastic (trays, netpots, etc) to setup : Its quite a bit of plastics. If folks don’t reuse the plastics, they are just harming the environment.
My first attempt ends as a failure. Has taken more than a month but the growth of spinach in hydroponics is lesser than that grown normally.