We have learned how to successfully grow tomatoes in a sub-tropical climate in Guatemala through a lot of experience, and a lot of failure. 😊
In San Marcos La Laguna on Lake Atitlán, at over 1,500 meters of altitude, there are intense conditions that can make it difficult to grow delicate plants such as tomatoes, organically.
Through trial and error, as well as consultations with professionals, we addressed the issues that can cause these sensitive plants to suffer.
Growing tomatoes outside
We started by growing tomatoes outside. Our soil was not very good, we didn’t know anything about maintenance or fertilization, and our result was quite poor.
But the rains made the biggest problem.
While we did have a harvest, a lot of the fruit split during the rain and rotted. Also, the plants got very sick after they started to produce fruit and didn’t live for very long.
After a few more attempts at growing tomatoes outside with similar or worse results, we knew that we needed to do something differently to get a better result.
Growing tomatoes under a roof and mesh netting walls
We built a structure to help protect these delicate plants from some of the elements.
Using wood beams, lamina roofing and a very fine mesh netting, we erected a structure.
This helped to keep insects out and to control the amount of humidity, but we still had a few of the same problems we had while growing tomatoes without a structure.
With a structure we could protect our plants from the heavy rains, but we still had to learn how to water and how much water to give to our plants.
When we started growing tomatoes inside of the structure we were hand watering the plants at their base, directly with a hose, and giving far too much.
Tomatoes really only need a little bit of water to live and if given more than just a little, they can get sick.
NOTE: Don’t over-water tomatoes!
We decreased the water that we gave to the plants and eventually installed a drip system to the base of each plant, that waters the plants evenly, and slowly. This really decreased the amount of humidity and therefore the amount of diseases that our tomatoes had.
To mulch or not to mulch?
That is the question.
When we began growing tomatoes, we were covering the ground with straw.
We thought it was good to keep the moisture in the earth and thought that it would also retain the nutrients of the soil.
Well, it definitely held the moisture in the space, but that was not a good thing.
Getting rid of straw decreased humidity and therefore disease. Straw can often harbor harmful bacteria due to holding a lot of moisture.
NOTE: Having no mulch, in this case, helped!
How to deal with Tomatoes with too much foliar growth?
While the tomatoes had disease, that wasn’t the only problem that they had.
The tomatoes were growing, but they were growing so big and with so much foliar growth that we didn’t get much of a fruit harvest as well as ended up with disease due to the amount of humidity.
When the tomatoes have so much foliar growth, they grow into each other. When this happens, there is less air flow, and the humidity increases.
When plants put so much energy into leaf production and horizontal growth, they don’t have much energy left to produce fruit.
One thing that we tried to do to help with the air flow was installing fans. This didn’t work and made things worse. The strong air flow actually spread the diseases throughout the enclosed area.
SOLUTION: We began pruning the plants from an early age to help with disease and to increase fruit production. The first three or four leaves from the bottom of the plant should be pruned three weeks after transplanting the plant. The “suckers”, or small shoots that grow between the main stem and the branches are also cut.
We cut these shoots on a weekly basis so that the plant keeps energy for branches that produce more fruit and also so the plant grows more vertically and less horizontally.
Along with pruning the plants, we learned a method of tying the main stem to the ceiling to help the plant grow straight and vertically.
This involves wrapping the string around the main stem in a specific way to not damage the stem, but supporting the plant in its vertical growth.
how to support tomatoes vertically by tying them with a string?
(WATCH VIDEO BELOW)
Tomatoes flourish in full sun
The location where we built the structure receives sun for about half the day. After a few attempts with little fruit, we realized that the plants were lacking sunlight and this was also affecting the harvest.
To give our plants more light, we installed grow lights.
The results did improve, but the plants were still not producing to the full potential.
Our structure was made of mesh, not just it’s walls, but the roof too. Then on top of that we also put a transparent plastic roof. While this was keeping out harmful insects, it was blocking quite a bit of UV rays.
SOLUTION: We took away the net mesh layer from beneath the roof and made sure insects still could not get in by attaching the mesh wall to the roof. The grow lights seemed unnecessary at this point so we removed them. After doing this, we had the biggest crop to date.
How to make a natural insecticide to protect tomatoes?
There were a few different insects that were damaging our crop, but the main culprit were the caterpillars.
SOLUTION: To help get rid of the caterpillars especially, we started to make an insecticide that consisted of garlic, chili, and tobacco. We boil these ingredients for a number of hours, wait until it cools, and strain it. When the insecticide is ready to use, we spray it on the plants on a weekly basis. We also used a bacteria that helps decrease the population of these harmful caterpillars called bacillus thuringiensis.
What to do when heirloom tomato seeds start to show mutations?
Although our yield increased dramatically, we learned that the plants had a lot of mutations. This limited our yield because instead of continuing their growth vertically, they grew horizontal instead, regardless of the pruning that we did.
They produced more “suckers” in unusual places and multiple suckers growing in the same spot. The seeds that we used were heirloom seeds.
Heirloom seeds are nice because of the unique varieties that you can grow, and because you can save the seeds to produce your own tomatoes. The negative side to heirloom seeds are that they can contain mutations.
SOLUTION: We started using seeds that were bred specifically and carefully to not have mutations.
What soil mix do the tomatoes require?
Throughout this process we learned a lot about the importance of soil and nutrients in relation to fruit production and plant health.
To begin with, the soil was horrible and not very suitable for growing; it was a very hard, dense layer of dirt and clay. It lacked nutrients, organisms, and microorganisms.
It also lacked the proper loose texture required to properly grow any plant.
SOLUTION: We started with excavating 1 meter deep. After that we sifted soil and added white sand and compost. This was an important and necessary step, although did not provide the plants with all the food that it required to produce a lot of fruit.
We discovered that adding worm compost as well as chicken compost to the general soil mix gave the plants more nutrients and helped the overall growth and health of the plants.
As well, we began fertilizing the plants with the chicken compost and worm compost by applying small quantities to the base of the plant throughout its cycle. Once again, this boosted the plants health and growth.
What to do when tomato flowers rot and tomatoes fall before maturation?
We noticed that the plants still had some weaknesses. Flowers would at times rot before turning into fruit, fruit would fall to the ground before maturing, and the plants' overall health would deteriorate while fruiting.
We realized that the plants were missing two important nutrients; potassium and calcium.
SOLUTION: When the first fruits appear, we spray the plants with calcium and potassium and again when the second clusters of fruit appear. This helps the plants produce fruit and to continue growing after the first fruiting.
Tomatoes have a lot of specific needs to attend. They are very sensitive plants, especially in a places like Guatemala, or near a large lake, where there's lots of humidity.
Over time, we learned how to tend these plants in ways that help their growth, giving them what they need to produce lots of fruit with less disease.
It took us a few years to acquire all of the detailed information that I wrote above, and we are still learning more.
After applying all of these details, we have been successful in harvesting quality tomatoes. We are still learning how to improve our tomato plants, and how to improve the quantity and quality of the tomatoes that we produce. It's a constant learning process that we're going through, always seeking to grow healthier plants.
If you have any questions about growing tomatoes, go ahead and write us at: firstname.lastname@example.org