Grow Lighting: Tiny Tomatoes Indoors

June 8, 2023

Can I grow tomatoes indoors?

How do I light my indoor tiny tomatoes?

Wish you could grow tomatoes indoors?

You can! One of the most successful ways is to go micro...by growing miniature tomato cultivars, like Micro Tom (there are lots of others these days!). Micro tomatoes are perfect for indoor gardeners who have limited space don't want to use HID grow lighting (the BIG ones).

Growing a single miniature tomato plant with a 20-30W LED spotlight is totally doable and the perfect beginner project. Tiny tomatoes are usually around 50-60 days to maturity from seedling stage.

If you want to get specific about the light metrics:

  • Tomato seedlings will need a DLI of about 15 Mol/m2/D for the first 2-3 weeks with a PPFD of about 200-300 umol/m2/day.
    • As soon as you see germination occurring turn on your grow light! You don’t want your seedling to stretch due to lack of light. Germination should occur anywhere from 7-10 days, give or take depending on home temperature. Warmer temperatures will speed germination
    • Place your 20W LED grow lamp 12 inches above your seedling pot and run your lamp for 12 hours
    • This will give your seedling a PPFD of approximately 200-300 umol/m2/s
  • Then bump to a DLI of around 20 Mol/m2/day with a PPFD of about 400-600 umol/m2/day for vegetative growth phase, for the next 3-4 weeks.
    • Place your grow light about 8-9 inches above your plants and rune the lamp 13-14 hours
    • This will give your seedling a PPFD of approximately 400-600 umol/m2/s
  • Then shift to a DLI 25-30 Mol/m2/day with a PPFD of around 600-900 umol/m2/day for the flowering and fruiting phase, which is usually around another 3-4 weeks.
    • Place your grow light about 6-8 inches above your plants and run the lamp for 14 hours.
    • This will give your seedling a PPFD of approximately 600-900 umol/m2/s

The duration of each of these lightings stages will depend on the cultivar you're growing, and how many days it takes for that cultivar to reach maturity.

Shifting the intensity of the light (PPFD) can be achieved by raising your lamp (decreases the PPFD) or lowering your lamp (increases the PPFD), and your DLl (Daily Light Integral, how much total light the canopy of your plants receives each day) is influenced by how long you leave your grow lamp on. Running your lamp longer increases DLI, while running your lamp fewer hours decreases your DLI. Note that my recommendations are generalized and your growing conditions and the lamp your using will vary.

Take care to be mindful about the heat generated by your grow lamp. Sometimes the desired PPFD requires a lamp to be placed too close to a plant or seedling that could be sensitive to the amount of heat generated by your grow lamp. So, you'll have to play around a bit with your lamp distance and monitor how your plants respond...favorably, or not!

These are typically determinate tomatoes, so once they fruit and you harvest, you should grow another plant! Consider seeding succession crops a couple of weeks apart so that you always have tiny tomatoes at your fingertips!

If you're looking for a tutorial on growing tiny tomatoes indoors from seed to harvest, read "How to Grow and Harvest Tiny Tomatoes Indoors".

To learn more about how to grow micro tomatoes indoors read "10 Steps: Grow Tiny Tomatoes Indoors from Seed to Harvest"

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