I have a number of squash and similar plants (zucchini, cucumber) which I started indoors under a fairly strong LED grow light. They are still under a foot tall each.

They were suffering from some fungus gnat issues which I have been treating with BTI (Mosquito dunk watering) and the leaves were yellowing and dying off. Even after the fungus gnat problem has been substantially improved, they are still not growing very well with moderate bottom watering and good light exposure (not too much and not too little - about 240k lumens or 2-3ft from the led grow light). Unsure if the stress that forced them to flower was the fungus gnats or not - they killed several seedlings and seeds before they took off but I see very few fungus gnats now.

I noticed they are all starting to produce flowers already which seems like it may be the real issue now. As flowers take a lot of energy to produce, it would seem to fit that some of the leaves would be getting drained to create the flowers. Unfortunately, they only have 1-3 true leaves and their sprout leaves are dried up so they are really in no place to flower.

Is there a reliable way to force them (gently) back into vegetative growth so they stop making flowers this young? Either by controlling the intensity of light or how long the light exposure is? Other methods?

I used the same light last season to grow the same plants and did not run into this issue but also did not have a fungus gnat problem as bad (as far as I know). Cutting off flowers?

Edit: other detail that may be pertinent is that the room they are in does not cool down much. It's an average low of 76F and an average high of 81F every day. Does this trigger flowering?

sad squash

outside squash planted weeks ago

  • 1
    Have you considered that flowering can be a Hail Mary approach to survival? Like „I probably won’t make it much longer, let’s at least try to produce some seeds so my descendants can start over”?
    – Stephie
    Commented May 18, 2021 at 16:39
  • Of course - that is a concern and could be the response I am seeing.
    – Enigma
    Commented May 18, 2021 at 17:01
  • Squashes germinate easily and grow quickly. My advice is to direct sow outdoors or germinate just a couple weeks before they go outdoors. Commented May 19, 2021 at 2:33

2 Answers 2


You can pinch off the flower buds until you're ready to plant outside. I don't recommend changing light and heat at this point because it can make seedlings leggy and weak. How much longer do you plan to keep it indoors?

  • Not long - I was planning to keep them indoors until they recovered and showed some stronger growth patterns but it may be that keeping them indoors in these conditions are what is exacerbating the issue so... I was leaning towards moving them outside soon.
    – Enigma
    Commented May 18, 2021 at 17:01

This may not be the issue but I did find this information:

Over all mean temperature is most important in sex expression, however, night temperature plays a significant role since warm nights lead to increased male flowers production at a given temperature compared to warm days. - https://www.agricultureinindia.net/cultivation/summer-squash/how-to-cultivate-summer-squash-vegetables-agriculture/18652

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