Growing San Marzano Tomatoes in Kratky Hydroponics – Update: Week 3

I wouldn’t have believed it a month ago when you said I could grow tomatoes so easily in Kuwait’s hot desert weather; but here I am, just growing tomatoes. Of course I cheated a little by growing them inside the house, in a climate controlled area… and then I removed the soil and decided to grow them hydroponically.

And they are still growing!

My little plant babies are now three weeks old, and wow have they grown. This was them only one week ago:

Their stems had just started to turn brownish tinged close to the cloning collars. They both also had two new branches.

And this is them now, at three weeks old:

I just can’t believe how fast they are growing. I can turn my grow lights off at night, then when I re-enter in the morning they have grown an entire branch! No joking, I have seen an entire baby branch just pop up in the space of a few hours.

I have preemptively placed their first trellis support bars. Since we are using custom painted Ikea Ivar cabinets to hold our plants, we bought the bottle rack as a DIY trellis. This provides some basic support for the plants, and lets me tie them in place. We can also easily raise or lower the bottle rack as needed, and even add more as the tomatoes grow in height.

San Marzano Tomato Week 3, In Kratky Hydroponics
San Marzano Tomato Week 3, In Kratky Hydroponics

This is the weaker of the two tomatoes; he isn’t growing as fast. He now has four branches, two of which are fairly large. I noticed that once the dominate grower had put out one or two smaller branches, he had substantial increase in growth speed. I expect this one would probably grow much faster in the coming week.

The dominate grower is outpacing him pretty fast; he has a total of nine little branches all emerging. He’s also about 2″ (5cm) taller than his sibling. His centre branch is just touching the trellis bars, so hopefully in the next few days he will be resting against it and can be supported with the tie.

San Marzano Tomato Week 3, In Kratky Hydroponics
San Marzano Tomato Week 3, In Kratky Hydroponics

Both tomato plants seem to be developing some good root structures. I couldn’t lift the buckets out too high as the trellis bars are now in the way, but you can see the roots extend much further down into the bucket and nutrient water. The roots are nice and white, which is a sign of plant health when it comes to hydroponics.

San Marzano Tomato Week 3, In Kratky Hydroponics
San Marzano Tomato Week 3, In Kratky Hydroponics

Have you grown tomatoes hydroponically, or maybe traditionally in soil? Do you have any tips to share with a first-time grower?

Growing San Marzano Tomatoes in Kratky Hydroponics – Update: Week 2

One week ago I transplanted San Marzano tomatoes into a Kratky hydroponic container, and we were left wondering if they survived. Here is it in Week 1:

San Marzano Transplanted into Kratky, Week 1
San Marzano Transplanted into Kratky, Week 1

I’m glad to say that not only did they survive, they have started growing wonderfully!

San Marzano Tomato Seedling Week 2, In Kratky Hydrponics
San Marzano Tomato Seedling Week 2, In Kratky Hydrponics

The two tiny specks of leaves became much larger, and we now have four to five tiny new leaves beginning to grow on each section. The original leaves have definitely turned into stems, and hopefully they will eventually become branches.

San Marzano Tomato Seedling Week 2, In Kratky Hydrponics
San Marzano Tomato Seedling Week 2, In Kratky Hydrponics

The trunk of the tomato (can it be called a trunk yet?) is about three times the thickness than when I transplanted it. The fine fuzz on it has also thickened up and become much more apparent. I don’t know enough about botany to explain what this section does – if you know please let me know in the comments!

San Marzano Tomato Seedling Week 2, In Kratky Hydroponics
San Marzano Tomato Seedling Week 2, In Kratky Hydroponics

I’m not brave enough to lift the lid and look under. The water level was filled right to the brim of the container, and I mean right to the point of overflowing. I’m worried that if I lift it I will not only introduce light to the system, I may disturb the seedling as well. Maybe next week we can check out if there is growth.

Have you grown any tomatoes in hydroponics? I’d love to know your success (and failure) stories.

Transplanting Seedlings for Hydroponics Tips

A lot of people use hydroponic machines to start seedlings. Some people will start seedlings to transplant outdoors, and others will start seedings to transplant to larger containers. This post proves that I’m no exception: I just transplanted my San Marzano seedlings into their final Kratky hydroponic home.

Each method of transplanting has its own risks, as discussed below. By far the biggest risk of all is killing your innocent-baby plant. But if you follow the tips listed below, you will minimise the risk of being a plant slaughterer.

Also know that not all plants should be transplanted as some plants can’t handle root disturbance well, like spinach. You should only ever transplant healthy plants.

From Hydroponics to Soil

This is one of the most common methods to grow your plants; starting your delicate seedlings indoors and then planting in your garden when they are old enough to fend for themselves.

You should only transplant once roots have emerged from the bottom of the grow medium. If you wait too long then you risk stressing your plants.

Use grow medium that can be planted outdoors; trying to remove the plant from grow medium can be quite damaging to the roots. I tried separating my lettuce seedlings from the grow medium, and they definitely experienced shock.

Help your plants grow new roots, fast, by using root growth hormones. Whilst I haven’t used hormones on my own plants I have read online people recommending SUPERthrive Plant Vitamin Solution and HydroDynamics Clonex Rooting Gel.

Keep your soil well watered for a few days. You want the soil slightly damp, but not holding so much water that root or mould will grow. If your soil is well draining then consider watering a couple times a day.

You can also add a diluted nutrient solution to your water to help the plant get any extra energy it might need to grow new leaves and roots. This can be the same nutrients that your seedlings were growing in. Don’t give them full strength nutrients yet, as too much can actually harm your plants.

From Soil to Hydroponics

It is possible to transplant from soil to hydroponics, though many hydroponic growers like to keep their grow areas sterilised. Introducing dirt grown plants into a grow room can also bring the risk of unwanted bugs and diseases, potentially harming other plants (or even loosing all your crops!). I have personally lost entire crops from an exposure of an aphid infected plant, and so now I will only grow new plants from seeds.

Let your plant’s soil dry out prior to transplanting; dry soil is much easier to clean any dirt from the roots than wet. Once you have removed as much dirt as possible, then submerged the roots into a bucket of water and rinse any remaining residue. The roots need to be as clean as possible; dirt will contain bugs, algae, and can even damage some hydroponic pump systems.

Place your plant into a net pot and gently pull any long roots through the net pot holes. If the roots are fragile and just break, it’s better to keep them inside the net pot than risk damaging them. cover thoroughly with grow medium like clay pebbles. You need to ensure that no light can enter into your water reservoir.

Depending upon your hydroponic setup, make sure that air is still getting to the roots. Many people will use an air-stone to oxygenate your plant roots. If you are doing the kratky method then you should only submerge the lower roots and net pot, keeping at least half above the waterline to avoid drowning the plant.

Finally, your plant is going to go into shock, potentially a lot. It may look like you’ve killed the plant, with lots of leaves falling off or browning. Give it time and in most cases the plant will recover, anywhere from two days to a couple weeks. You may lose the original leaves as the plant will often abandon preserving those to focus on more important root growth.

From Hydroponics to Hydroponics

This will often be the easiest way to transplant seedlings, if you have planned out your plant growth before hand. The time to transplant is when the roots begin to emerge. Hydroponic roots are very fragile, so if they extend beyond the net cup then they are almost guaranteed to break.

If you know that your plant will need transplanting, try starting the seedlings in the final grow media such as rock wool. Simply transplant the entire cup or simply lift out the plant from one cup and transfer contents to a larger cup, adding more clay pebbles to block out any light.

Don’t make my mistake and wait too long: I transplanted some lettuce from peat moss (started in my Aerogarden) to cloning collars. The process or removing the lettuce seedlings from the Aerogarden net cups and washing out the peat moss caused them to mostly lose their fine roots. They looked dead for the first few days. It took them nearly a week to recover and start showing new growth.

Have you transplanted plants before? Share some of your tips in the comments below.

Transplanting San Marzano Tomatoes into Kratky Hydroponics

So far in my hydroponic journey I have been starting my seeds in my Aerogarden Bounty; it has the highest rate of success. There is just something this machine does better than I can, which is also a reason why I recommend anyone interested in hydroponics without the scary setup look at the Aerogarden product range.

On the 1st August 2019 I planted some San Marzano tomato seeds in my Aerogarden. It’s been a week (a bit longer by the time I got around to writing this article, but photos taken on date) and it’s time to transplant my tomatoes into their final home. Exciting!

When I previously transplanted some lettuce between the Aerogarden and Kratky setup, it didn’t go as well as I hoped: my poor plants suffered a lot of shock. I since learnt that I had let the roots get too large, and the transplanting process really hurt the plants (by ripping the roots right off!).

After learning from all my recent plant murder attempts, I am transplanting the tomatoes the moment the roots emerged; one week after planting the seedlings!

Here are the tomatoes just prior to transplanting. The seedling wearing his seed pod as a hat is so cute!

My kratky container is the Klämtare Box With Lid from Ikea. It’s a great option as the plastic they use is food-safe. It’s also large enough for two tomato plants.

I used a 3″ hole saw to drill into the lid, since I was using a 3″ net cup. You could always buy a hole saw kit with several sized pieces (I bought one of these kits as well). I also chose to transplant from the peat moss to a cloning collar, though this was a personal choice. Underneath the cloning collar was clay pebbles; it is recommended to add some grow medium underneath the collar in case you ever need to remove it, as it provides significant support to the plant and sudden removal could mean the plant falls over!

San Marzano Transplanted into Kratky, Week 1
San Marzano Transplanted into Kratky, Week 1

Fingers crossed that the seedlings survive now. I’ve only transplanted once or twice, and they have all survived, but taken a bit of stress in the process.

Have you transplanted tomatoes, or any other plants? Do you have any tips to share?