I have a watermelon seedling I planted 20 days ago and it's pretty much the same size now as it was then. I've read that simulating conditions like south Georgia can help, so I'm about to cover it with a large rectangular clear plastic bin with a few holes drilled in it.

1) does this sound like a good idea, and
2) is there some triggering event like the formation of flowers at which I should remove the bin?

The seedling is planted in a small mound, mulched with black plastic, and watered via soaker hose daily.

It's in the foreground on the right in this photo:

I think what will happen is that - even with the drilled holes - you will cook your plant(s).

I don't know of any method that will jump-start your plant(s), but if you feel you do want to cover it to increase the heat, I'd go with a plant row cover before I used a plastic bin.

And yes - you definitely DO have to uncover your plant(s) when they flower. These days many folks are having problems with squash & melons because of a lack of pollinators. You want to give them every opportunity to reach your plants - unless you want to do your own artificial insemination.

One more question - how much sun does your garden get? Because melons are true full-sun lovers. If yours isn't getting enough full sunlight, nothing you do is going to force it to reach its full potential.

I concur with the cooking.

Ever notice how greenhouses this time of year will do some combination of roll up their sides, open a bunch of windows, and run big fans?

I don't think you'll have enough control. If the holes are big enough to keep it cool in the afternoons or hot days, they'll be too small to provide additonal warmth in the mornings and afternoons and cooler days.

Darn.. ok. What I'll do is place something under the corners of the bin so that fresh air can easily come in from below.

Thanks for the tip on pollination.

Full sun, no, not completely. The photo was taken at 9 or 10 in the morning -- you can see there's a big tree (a Lombardi poplar, 30' tall and thin in profile) just off to the right of the garden, whose shadow wanders across the garden from 8-12 or so. The watermelon has full sun from approximately 11-4.

Sadly - your plan still will not work.

For one thing, raising the bin up off the ground still won't keep the plant(s) from cooking.

Second - melons need FULL SUN - at the very MINIMUM 6-9 hours of it. In other words - FULL SUN for that entire time. Unfortunately, melons & winter squashes are pretty unforgiving in the sun department.

Third - re: the above, your plastic bin will conveniently cut all the benefits that full sun provides, except for the heat. Heat isn't the only thing your plants get from the sun. Your plants won't be getting what little full sun they're getting now - they'll be getting it filtered by plastic. It would be like growing them indoors by a glass window.

Ditch the plastic bin idea & just realize that you either have to give up on growing melons in your non-full-sun garden, or you have to get them in the ground sooner, &/or find a sunnier, warmer spot to plant them. Your backyard does look/sound pretty shady.

Not sure of the exact latitude of Missoula, but up here near the Canadian border we're still getting nearly 16 hours of sun per day. Even with a bit of shade for part of the day, Magnafix could still be getting 6 - 9 hours of sun.

I don't think it's such a bad idea to try and warm the plants up. What could it hurt at this point? The worst that might happen is they wouldn't thrive, which they're not anyway. (By the way, mine don't look much better at the moment, if it makes you feel any better, and they are definitely in FULL SUN. All 16 hours of it.)

What about some other greenhouse-simulating ideas? Maybe put the cover on at night and take it off first thing in the morning to try and keep night temps up. Or put some water-filled jugs around it. Myself, I would try a few things and see how they work out.

Magnafix, this is the first year I've tried to grow melons. Up here, I think it's not the greatest year for anything in the squash family. Even my cucumbers are very slow, and they did great last summer (it was warmer). I know melons can be grown here. Just gotta work out how.

How about a tent of clear plastic instead?

I haven't tried this great idea yet, but another poster once suggested to me that a cheap way to support a "mini" hoop house would be to get some hula hoops from the dollar store, cut them up and use them to support row cover material.

Secure the material to the hoops with short lengths of old garden hose split lengthwise.

While it is true that plastic and other row cover materials do reduce total sunlight, at high latitudes and altitudes, we have to preserve heat, especially on clear nights when there is no cloud cover to keep a lid on things.

The best would be if you can uncover the plants during the time of direct sun, and then get them back under cover as soon as the sun is off of them.

I've got dutch lights (A/K/A "old storm windows") for some of my beds and in the early season, I pull them off just before leaving for work and put them back on as soon as I get home.

It's true that plastic, or any other cover will inhibit some of the sunshine, but preserving the heat at night is really important for those of us on the high plains and in the mountains.

Oh, and leave the ends open. This will allow ventilation and pollination. The important thing is a cover to intercept the heat that otherwise radiates out to the night sky.

Thanks everyone. There's a farm within 50 miles of here which is famous at the local farmers market for their tremendous, multi-truckload harvest of melons so I know it's possible.

My little plant is in the shade from 8-10 and 4-5 or so, but yea, it probably gets 10 hours of sun right now.

Here's some shots of what I'm actually doing in case people are imagining something different.

That looks interesting! Thanks for the pix.

I'd be interested to hear how things go for you over the next couple weeks trying it out. I'd also be interested in knowing your average day and night temps over the next couple weeks, and how you think that affected your melons-under-cover. I'm all about learning more season-extending tricks!

I'll check back in later this month with an update.

It hasn't died yet, and in fact might have grown a bit since I started this thread yesterday. We'll see. I'll certainly artificially inseminate as soon as the flowers open.

Lately Missoula has been 90ish days, 55ish nights, and looks like more of the same .

Hoo-eee! I'm guessing it's the night temps that are getting you. Surely they don't want to be any warmer than 90's during the day! Good luck!