Kratky Hydroponics: Effective Grow Lights for My Plants

lettuce plan after 3 days exposure to grow light
This was my green ice lettuce 2 weeks ago after being exposed to grow light for 3 days.
hydroponically grown lettuce plants after being exposed to grow light are ready for harvest
These are photos of the same lettuce after two weeks exposure to grow light, the one on the left has new shoots and ready for harvest.

I’ve had failed lettuce seedling in the first two weeks into Kratky hydroponics. Based on observation, several factors played in the success and failure of my seeds to grow into healthy plants – the summer heat, the lack of light exposure, quality of seeds (none of my cilantro seeds sprouted); and excess or lack of water. I knew, even before I started, that this would happen. I was not discouraged by it, however, and continued by replanting seeds and adjusting whatever needed was lacking or excessive. I even went as far as changing jars and disposing nutsol suspecting I may have not mixed them well.

The first factor, the summer heat, appears to be the contributory reason why some of my plants didn’t thrive. I check my plants everyday for signs of wilting, root damage, and foliar health. I noticed that when my “pechay” and lettuce were exposed in full sun from 6-10 AM, I observed signs of wilting at around 9 AM. This led me to change the plants’ position from the sun’s rays, even went as far as adding net curtain on my window despite the fact that it was not allowed in our condo. Still, the wilting happened. So after taking out some of the dead plants, mostly lettuce and pechay, I planted seeds anew. I waited for the seeds to grow 4 leaves before transferring them to bigger Kratky hydro jars. Because these plants were apparently more sensitive to heat, I decided to put them under grow lights instead.

Grow Lights

plants in Kratky hydroponics under grow light
My first ever grow light is this LED panel that emits red and blue lights – making the whole set-up give out a magenta glow.

To maximize the light, per advise by members of a hydroponics group, I added illustration boards covered in aluminum foil at the two sides of table and later on added insulating sheets at the other two sides thereby fencing the plants in, so that light will bounce off and hit the plants on all sides. When one of the mustard plants seating by the window showed signs of wilting, I also sat it beside the lettuce under this grow light and it showed improved appearance.

I read that the red and blue light spectrum is great for green leafy vegetables from seedling to mature plants. So when someone offered to sell me his secondhand LED grow light, I did not hesitate to buy it from him. It was a good deal that I could not pass up especially because supplies were hard to get by due to this pandemic. I noticed that in two weeks of exposure, lettuce under this grow light shot up like crazy. It was as if they had only been waiting for this grow light all along. I was happy to see my lettuce grew at such a rapid rate that I’ve also added my mustard, basil, thyme and tomato seedlings on the table beside the lettuce.

When other plants started showing signs of wilting, I decided to add insulators around the hydroponic jars after realizing that the heat is possibly heating up the nutsol, thus, cooking my plants’ roots. The socks, white paint, and aluminum foils weren’t enough to protect the plant from the summer heat. I then decided to add and try out another type of grow light which is a simple 6500K LED bulb emitting 800 plus lumens from a local hardware, ordered online.

LED bulb as a cheap alternative grow light for plants
The LED bulb, as expected, does not emit too much heat and it seems to be effective in reviving this pechay plant which very nearly died on me more than one week ago. I also covered this area around the bulb with insulators to bounce off the light and expose the plant on all sides.

Although it was recommended by some of the gardeners I followed on Youtube, I wasn’t totally convinced that the bulb would work. So when I bought the bulbs, I was a skeptic who was gonna use the bulbs as study lamp in case they didn’t work for my plants. Turned out I was wrong – the bulbs did work. I noticed new leaves growing out of the pechay plant that was dying on me prior to exposure to this bulb (photo above). I also noticed that the leaves of my bell pepper and young lettuce had turned their leaves towards the bulb – which tells me that phototropism is happening.

LED bulb as a cheap alternative grow light for plants
A wider look at the bell pepper and pechay plants exposed under the LED bulb. Right under the bulb is a young lettuce plant that has showed its young leaves 2 days ago – another proof that the bulb works.
basil plants growing just beside our condo unit window
I’ve exposed these basil plants to the red and blue grow light for about a week before putting them back beside the window. Basil plants have so far been the most resilient of my plants, surviving even with minimal exposure to the sun.
soil gardening by the fabulous scientist
A friend also offered to buy loam and garden soils for me so I could venture into soil gardening too.

When a friend offered to buy loam and garden soils for me, I immediately said yes. In case you don’t know, the reason why I didn’t go into soil gardening was because I almost killed my husband’s plants (he was the green thumb) twice before. After that, I felt that I had a black thumb for gardening. By now, I have an appreciable rate of success in Kratky Hydroponics, I decided to give soil gardening a try again.

leggy pechay due to low light
My first and second batch of pechay were leggy. Because the summer heat is too much, I didn’t put the seedlings under full sun – I suspect this was the reason why they were leggy, growing long stem in search of the sun.
sweet potato vine in potted soil gardening
I grew this sweet potato from water for two weeks before transplanting to soil. It appears resilient has even grown more leaves.
flowering plant from Mongpong Island growing in an improvised self-watering pot out of PET bottle
I picked up the seed pot (one beside the popsicle stick label) during our beach trip in Mongpong Island last February. The flowers were yellow and abundant so I decided to bring a seed pod home. The seeds just sprouted yesterday after being in the soil for 4 days.
Mongpong flowering plant
The yellow flowers were obtained from the same plant where I got the seed pod. Hopefully the seedlings will survive in the loam soil I planted them in.
improvised self-watering planter using PET bottles
I have also started making self-watering plants out of paracord and PET bottles. I hope this newly planted spring onions will grow to mature plants in this self-watering pot.
Self-watering Kratky Hydroponics set-up using watering spike
I installed self-watering spikes on some of the plants then also tried one on my hydroponically growing tomato but instead of water, it’s dropping nutsol on the hydrotons.

One of my qualms before I got into urban gardening and hydroponics was that there won’t be anyone to attend to the plants while we are away for vacation. So when I started planting, one of the things I looked for online was a sort of automatic irrigation system for my plants. I found ones that look complicated that I gave up. When I typed in “self-watering device” on Shopee without really knowing what to look for, I came across a photo of this spike (photo above) with tiny faucet. I got intrigued and decided to order. But because of the pandemic, Shopee had limited the items available for ordering for essential items, the spike, sadly was excluded. Two week into quarantine, gardening items were declared essential, possibly due to influx of people deciding to grow their food, that the spikes became available for online purchase. I ordered a set of 12 which arrived today. I tested them on my plants and was sadly disappointed at first the the water was not dripping. I realized that air needs to be inside the bottles so I poke a hole on the top portion of each bottle to let some air in (bottles were half full) and water started pouring out of the tiny faucets. I then regulated the flow of water using the tiny knob to mere drops because I don’t want to drown my plants.

Then, an idea struck me that I can also use the spike to refill nutsol into my hydroponics jars. Among my plants, tomatoes, basil and white sitaw consume the most amount of nutsol. If I were to be gone for two days, I was pretty sure that these plants will run out of nutsol because the jars they are planted in are less than 1.5 L in volume. So I am testing the spike now on one of my tomato plants just to see if I need to adjust the rate of recharge from the spike.

self-watering spike for potted plants
Our aloe vera plant with self-watering spike.
root check of a Kratky hydroponics tomato plant
Once in a while I conduct root check on my plants by removing the insulating cover or pulling the net pot out. So far, only one plant showed serious algal growth that smelled like drainage. I had to throw away the plant and clean the plastic jug with dishwashing liquid to kill off the algae.
essential oils to help protect plants from pests
I add a few drops of these essential oils into water spray to ward off harmful insects off my plants. So far, the spray has been effective in controlling bugs and ants.

Since a lot of people from outside the Philippines are asking where they can possibly get some of the products mentioned here, I am including my affiliate links with Amazon below. Please take note that by buying these stuff through my affiliate links, I get a bit of commission that will help me fund this website and keep it up and running.

Kratky Hydroponics System kit from Amazon
Indoor Kratky Hydroponics System with Grow Lights
Grow Light bulbs

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