whether to start indoors or out

[Cutworm]

Hi, after 30 years of starting my tomatoes in a propagation chamber in an unheated cellar, it was time for a change--and hopefully an improvement. No more transplanting from cells to Solo cups--I bought a bunch of CowPots and would eliminate that step. The 30 year old shop lights were going to get an upgrade to LEDs. The ballasts are probably on borrowed time anyhow. And then it hit me---I have a long winter ahead and material on hand to build a cold frame so why not explore that route a little. It would, as I understood it, minimize the hassle of hardening off. I like simplicity.

I have a 4'X4' boxed raised bed with 24" tall sides attached with screening to keep the rabbits out. I was thinking of wrapping the sides with u/v stabilized poly and fabricating a top---either with more poly or possibly polycarbonate---and an automatic opener.

I was thinking I could start the seeds 6 weeks prior to my last frost, which is May 6 here in Southeast Mass. At some point, I would move them out to the cold frame. That was the question---at what point.

I've read everything from "as soon as they're up, out they go" to one to two weeks prior to plant out date, just to harden them off. If moving them out shortly after germination, then there probably wouldn't be any point in buying LED tubes.

I have electricity available in the garden so is there any point--or advantage--to moving the heat mat out to the cold frame and just sprouting the tomatoes out there---bypassing all of the indoor stuff. If starting outdoors 6 weeks prior to last frost, what about a supplemental heat source and at what temperature---50 degrees?

Thank you in advance for anything you can share.

[MissS]

Welcome to the Junction @Cutworm !

Tomato seeds will germinate when soil temperatures are at 70 - 82 degrees. Given that, I would start the seeds indoors. Once they are up and have one set of true leaves then I try to give mine the cool treatment to make them shorter and sturdier plants. This is when I suggest that you move them out to the cold frame. You will have to watch the temperatures in your cold frame as well. You don't want your new plants to overheat once it starts to get warmer out nor do you want them freezing either.

[worth1]

They won't do anything with soil temperatures down below about 65F.
Another thing I discovered with the cold treatment is if you bring them in at night where it's warm they grow in the dark.
It's pretty well documented that plants take up energy during the day from the sun and put on new growth at night.
I did this test myself a few years ago.

[Tormato]

Hi, after 30 years of starting my tomatoes in a propagation chamber in an unheated cellar, it was time for a change--and hopefully an improvement. No more transplanting from cells to Solo cups--I bought a bunch of CowPots and would eliminate that step. The 30 year old shop lights were going to get an upgrade to LEDs. The ballasts are probably on borrowed time anyhow. And then it hit me---I have a long winter ahead and material on hand to build a cold frame so why not explore that route a little. It would, as I understood it, minimize the hassle of hardening off. I like simplicity.

I have a 4'X4' boxed raised bed with 24" tall sides attached with screening to keep the rabbits out. I was thinking of wrapping the sides with u/v stabilized poly and fabricating a top---either with more poly or possibly polycarbonate---and an automatic opener.

I was thinking I could start the seeds 6 weeks prior to my last frost, which is May 6 here in Southeast Mass. At some point, I would move them out to the cold frame. That was the question---at what point.

I've read everything from "as soon as they're up, out they go" to one to two weeks prior to plant out date, just to harden them off. If moving them out shortly after germination, then there probably wouldn't be any point in buying LED tubes.

I have electricity available in the garden so is there any point--or advantage--to moving the heat mat out to the cold frame and just sprouting the tomatoes out there---bypassing all of the indoor stuff. If starting outdoors 6 weeks prior to last frost, what about a supplemental heat source and at what temperature---50 degrees?

Thank you in advance for anything you can share.

Southwestern Mass, here. You'll likely be at the mercy of the weather, just like me.

I germinate indoors (3 to 4 days for 90% of seedlings to emerge), then move seedlings outside during the day, and move them inside at night. Here, this usually goes on for about three weeks. By the fourth week, they can generally stay outside overnight with good weather. Plants are ready to transplant at 4 weeks. I start early May and transplant out late May. That's all with great weather.

In poor weather conditions, cold, wind, clouds, rain, it can take up to 10 weeks. Small, but not tiny, seedlings can survive being indoors for about 12 to 14 days without getting any sunlight. After several days inside, then going outside into the sun, there will be some leaf tip damage, as they are no longer completely hardened off. Plants that stay outside most days need no hardening off.

The last week or so, prior to transplant, plants need to be watered twice a day if they are in 8 ounce plastic containers. Cowpots sound like they will draw some moisture away from the plant. However, I'm guessing that they are likely larger than 8 ounces.

With about 150, or so plants, some years it's very easy, for me, and some years it's very hard.

[Tormato]

Hi, after 30 years of starting my tomatoes in a propagation chamber in an unheated cellar, it was time for a change--and hopefully an improvement. No more transplanting from cells to Solo cups--I bought a bunch of CowPots and would eliminate that step. The 30 year old shop lights were going to get an upgrade to LEDs. The ballasts are probably on borrowed time anyhow. And then it hit me---I have a long winter ahead and material on hand to build a cold frame so why not explore that route a little. It would, as I understood it, minimize the hassle of hardening off. I like simplicity.

I have a 4'X4' boxed raised bed with 24" tall sides attached with screening to keep the rabbits out. I was thinking of wrapping the sides with u/v stabilized poly and fabricating a top---either with more poly or possibly polycarbonate---and an automatic opener.

I was thinking I could start the seeds 6 weeks prior to my last frost, which is May 6 here in Southeast Mass. At some point, I would move them out to the cold frame. That was the question---at what point.

I've read everything from "as soon as they're up, out they go" to one to two weeks prior to plant out date, just to harden them off. If moving them out shortly after germination, then there probably wouldn't be any point in buying LED tubes.

I have electricity available in the garden so is there any point--or advantage--to moving the heat mat out to the cold frame and just sprouting the tomatoes out there---bypassing all of the indoor stuff. If starting outdoors 6 weeks prior to last frost, what about a supplemental heat source and at what temperature---50 degrees?

Thank you in advance for anything you can share.

Southwestern Mass, here. You'll likely be at the mercy of the weather, just like me.

I germinate indoors (3 to 4 days for 90% of seedlings to emerge), then move seedlings outside during the day, and move them inside at night. When I say emerge, all it has to be is for part of the stem to show, the head of the plant doesn't have to appear. This usually goes on for about three weeks. By the fourth week, they can generally stay outside overnight with good weather. Plants are ready to transplant at 4 weeks. I start early May and transplant out late May. That's all with great weather.

In poor weather conditions, cold, wind, clouds, rain, it can take up to 10 weeks. Small, but not tiny, seedlings can survive being indoors for about 12 to 14 days without getting any sunlight. After several days inside, then going outside into the sun, there will be some leaf tip damage, as they are no longer completely hardened off. Plants that stay outside most days need no hardening off.

The last week or so, prior to transplant, plants need to be watered twice a day if they are in 8 ounce plastic containers. Cowpots sound like they will draw some moisture away from the plant. However, I'm guessing that they are likely larger than 8 ounces.

With about 150 plants, some years it's very easy, for me, and some years it's very hard.

So, it comes down to "weather" to start indoors or out.

Perhaps the best thing to do is to start some plants the old way, and some plants the new way. It might be more work, but it's sort of an insurance policy against complete disaster.

[brownrexx]

I don't grow huge amounts of plants like many of you. I only grow about 20 tomato plants but I like having them indoors. I have a small wire shelf unit with my lights in my sunroom so when we sit out there, I see the growing plants. I start my seeds at the end of March and they get planted out in May. When they are large enough to go outside, I pot them into 4" pots and they live on my front porch which has a roof but is open to the air.

20190414_151813 by Brownrexx, on Flickr

20190422_185310 by Brownrexx, on Flickr

[Cutworm]

Thank you all for the response. I never expected so much so soon.

If I'm going to do everything different---and hopefully better---I'm trying to develop a set of hard and fast rules, the "basics" to follow--which will then be adjusted according to what is happening at the moment

So, once the seeds have germinated, the seedlings are safe to move into the cold frame during the day---with no need to harden off? Just pop them right into the cold frame?

If that is the case, can I put the heat mat (good industrial version) out in the cold frame (on a piece of plywood) and start the trays of about 60 CowPots right out there in the cold frame?

This would mean just potting up the seeds and moving them outside to the cold frame and then just wait till the 6 weeks are up to transplant?

Does anyone have experience with the automatic openers?

I guess I am trying to take this as far as I can in the streamlined direction. After I'm comfortable with the expected results, I'll weigh the risk vs benefits and decide which way to go. In the end, I may wind up doing nothing different---but it wouldn't be for lack of ... exploring the possibilities?

Thank you all again !

[AZGardener]

I would try a few in the cold frame and the rest indoors. That way, if the cold frame doesn't work you have back up plants.
I start my seeds indoors under lights in January to plant out mid-February. My climate is very different than yours so not much help on cold frames.
Good luck!

[Tormato]

Thank you all for the response. I never expected so much so soon.

If I'm going to do everything different---and hopefully better---I'm trying to develop a set of hard and fast rules, the "basics" to follow--which will then be adjusted according to what is happening at the moment

So, once the seeds have germinated, the seedlings are safe to move into the cold frame during the day---with no need to harden off? Just pop them right into the cold frame?

If that is the case, can I put the heat mat (good industrial version) out in the cold frame (on a piece of plywood) and start the trays of about 60 CowPots right out there in the cold frame?

This would mean just potting up the seeds and moving them outside to the cold frame and then just wait till the 6 weeks are up to transplant?

Does anyone have experience with the automatic openers?

I guess I am trying to take this as far as I can in the streamlined direction. After I'm comfortable with the expected results, I'll weigh the risk vs benefits and decide which way to go. In the end, I may wind up doing nothing different---but it wouldn't be for lack of ... exploring the possibilities?

Thank you all again !

After germination, do not delay moving them outside. There is no need to harden off. If the cold frame protects from cold, wind, rain, etc..it looks like they can be outside during the day in fairly severe weather. I highly recommend 4 days, or more, of constant 70 plus degree temps for germination, which generally means indoors.

There can't be any expected results. One can never get comfortable with the true results until you have one year of good weather, and one year of lousy weather, under your belt. One year I went 14 straight days with no sun, just clouds, cold, wind and rain. Another year I delayed starting seeds by a week, as the 10 day forecast predicted miserable weather.

Doing this for twenty years, in May not April, my results are that outdoor growing is far superior to indoor growing, or far inferior to indoor growing, without ever knowing which is going to happen.

[karstopography]

I would not be doing mine outdoors in any normal year, but it’s 7 am and 73 degrees outside. That’s warmer overnight outside the house than it is inside the house with the A/C running. Supposed to be like that, warm nights, warmer days, until Saturday. I’ll move them indoors then under the grow lights. I suppose we go with whatever weather is being dished out.

[Tormato]

I would not be doing mine outdoors in any normal year, but it’s 7 am and 73 degrees outside. That’s warmer overnight outside the house than it is inside the house with the A/C running. Supposed to be like that, warm nights, warmer days, until Saturday. I’ll move them indoors then under the grow lights. I suppose we go with whatever weather is being dished out.

Perhaps your sun angle is too low for strong sunlight, now. But, if indoors for many days and then moving them outside, there could be some leaf damage. And, there's only one way to find out. If the outside stays warmer than inside, overnight outside sounds good, then a few hours in direct sunlight, and the rest in partial sunshine might work, until you know they can take full sunshine all day.

[Cutworm]

Thanks for all of the input---it is much appreciated. The adult in me knows I should hedge my bets and try both approaches simultaneously---some indoors and some outdoors. Since I'm revamping my entire approach to seed starting (it wasn't broken so I don't know why I feel a need to fix it), and since my fellow Massachusetts resident tells me to transfer the plants out to the cold frame as soon as they germinate, I'm throwing caution to the wind and going for seedstarting V2.0

Instead of setting up my insulated propagation chamber with lights in my unheated cellar (55 degrees), I can just unfurl my heat pad (300 watt band heater) for bottom heat on my workbench. Typically, I also have germination in 3-4 days. I put the tray containing the cells in another tray with an inch or so of water in it. Then I put both on the heat mat. The heat mat heats the water, which retains the heat much better than had I just put the cell tray on the mat. Although the heat mat stays on longer, I think it's preferable to the short cycling of just having the cell tray on the mat. I should add that there is a temperature probe in the cells that turns the heat mat on/off. It is set for 80 something degrees. Since the seedlings are now going to be in individual pots instead of cells, as they germinate, I can move them directly out to the cold fame---no need to set up the propagation chamber and lights.

The "spare" bed in the garden is 4' X 4" and 2' tall (the sides are a picture frame of 1 X 4 pressure treated boards with 1/4 screening in the opening). I plan on installing 1" foil backed insulation board on the insides from Home Dept ($20) and building a frame for the top, which will have leftover greenhouse poly for sheathing. I was toying with clear Lexan but from what I've read, the diffused light from the poly film is supposed to be preferable for tomatoes---and I have some of that already.

Now, I need to provide supplemental heat. Since I'm not planning on growing anything over the winter, just trying to keep seedlings from freezing for about the month of April, I explored all of the solutions out there that I could think of i.e. from umpteen variations of space heaters, livestock tank heaters, birdbath, pond and aquarium heaters. With the market over-run with Imported junk, I didn't want to gamble on most of them. Ultimately, I'm going to bite the bullet and buy a band heater for a metal 5 gal bucket. It's an industry standard commercial product actually built in USA. You attach it to a 5 gal black metal bucket---black for any solar gain during the day---and metal filled with water as a radiant heat source when needed when the sun isn't shining. It is thermostatically controlled (50-->425 degrees) with a 550 watt heater. I figure I can set it up a couple of weeks or so ahead of seed starting and see how well it stabilizes. When the lights were out in the cellar, the stocky plants seemed to benefit from the 55 degrees so I really don't need to boost the temperature all that much to maintain a similar temp outdoors. I guess I should put the bucket in the center of the bed. I'm hoping that whatever temperature is in the near vicinity of the bucket is not harmful for the seedlings. If, by chance, the radiant heat doesn't disperse as well as I might like, I do have a small computer type fan for that.

The band heater isn't cheap---$129 But---if I can start seeds by just rolling out a mat in the cellar and, as they sprout, putting the individual pots out in a heated cold frame until planting time---that will be an enormous improvement over my present system--- If it works

I relay all of this in the off chance anything I've done may be of help ---or detriment---to someone searching out a similar approach some day down the road.

Happy New Year !

[worth1]

I would not be doing mine outdoors in any normal year, but it’s 7 am and 73 degrees outside. That’s warmer overnight outside the house than it is inside the house with the A/C running. Supposed to be like that, warm nights, warmer days, until Saturday. I’ll move them indoors then under the grow lights. I suppose we go with whatever weather is being dished out.

Perhaps your sun angle is too low for strong sunlight, now. But, if indoors for many days and then moving them outside, there could be some leaf damage. And, there's only one way to find out. If the outside stays warmer than inside, overnight outside sounds good, then a few hours in direct sunlight, and the rest in partial sunshine might work, until you know they can take full sunshine all day.

I have tomato seeds sprouting on their own right now.
I also have a volunteer plant with tomatoes on it.
I think it's now an F4 Juliette.

[Cutworm]

I'm jealous.I just love opening the propagation chamber door and getting hit with a blast of warm air and that green seedling smell

[worth1]

These are just seeds that come up on their own in a container.
I don't even take care of them.
They even came up after last year's bug freeze.
I also have some volunteer wild pepper plants growing from a wild pepper plant.
Here's one from just the other day.

20211227_154220.jpg

[Cutworm]

In case anyone was curious how my experiment worked out---it worked out great.

The band heater on the metal 5 gal pail maintained 55 degrees on a couple of nights last week when the temp dipped to the low twenties here. On most other nights, when the night low was in the thirties, it maintained low to mid sixties inside. The UniVent works exceedingly well to drain off excess heat whenever the sun shines. As soon as it hits 75, it starts to open.

Presently, I have 38 assorted plants growing out there and they are all nice and green and happy looking. I can't get over how easy this will be each spring from now on. I had no idea. Plant seeds in CowPot and place on heat pad (in cellar). 3-5 days later, as soon as they germinate, move out to hot bed/cold frame. Done. When the time comes for transplanting, plant them pot and all.

When I put the seeds in the CowPots, watered them and placed them on the heat mat, I had put humidity domes over the pots. This was a mistake. They became saturated. I took the domes off and put a piece of fabric over the pots to help hold in the heat and this worked great. It was a fair amount of work retrofitting the old raised bed fence into a hot bed/ cold frame---it would have been easier to start from scratch---but modifying what I had was part of the challenge. There was a band heater for plastic pails which was less wattage but it did work out, after doing the computations, to be adequate for the space I had but I opted for the larger heater just to have that capacity in reserve. I took inspiration for how to fold the corners of the polyethylene cover for the top from canvas artwork. There are lots of videos on YouTube showing how to stretch canvas tight and neatly fold the corners. It came out great. The Univent is amazing as it continuously monitors and adjusts the lid. It took a couple of nights with a hi/lo thermometer to dial in the right heater settings.

[indysun]

do you have a pic of your coldframe setup?

[bower]

Yeah I would love to see a pic of it. The univent sounds amazing.

I've been thinking about doing something more constructive with water, it is so useful even just as passive heat. After many years of experimenting I found only one bottle that resists cracking even if all else fails and it freezes - it's a rectangular sided juice bottle with ribs in the plastic. Anyway I have collected a LOT of these (favorite apple juice brand) and used them willy nilly but I really liked best the advantage of having them underneath the plants, which is where I see zero cold trauma regardless of weather exposure, even better than surrounding the pots like a wall.
What I need to do is get over my laziness and saw up some 2X4 or 2X6 to the right lengths to build a little 'floor' container for the water bottles... I may actually do this, finally this year.

Thanks for telling about your project and spreading the inspiration.

[Tormato]

In case anyone was curious how my experiment worked out---it worked out great.

The band heater on the metal 5 gal pail maintained 55 degrees on a couple of nights last week when the temp dipped to the low twenties here. On most other nights, when the night low was in the thirties, it maintained low to mid sixties inside. The UniVent works exceedingly well to drain off excess heat whenever the sun shines. As soon as it hits 75, it starts to open.

Presently, I have 38 assorted plants growing out there and they are all nice and green and happy looking. I can't get over how easy this will be each spring from now on. I had no idea. Plant seeds in CowPot and place on heat pad (in cellar). 3-5 days later, as soon as they germinate, move out to hot bed/cold frame. Done. When the time comes for transplanting, plant them pot and all.

When I put the seeds in the CowPots, watered them and placed them on the heat mat, I had put humidity domes over the pots. This was a mistake. They became saturated. I took the domes off and put a piece of fabric over the pots to help hold in the heat and this worked great. It was a fair amount of work retrofitting the old raised bed fence into a hot bed/ cold frame---it would have been easier to start from scratch---but modifying what I had was part of the challenge. There was a band heater for plastic pails which was less wattage but it did work out, after doing the computations, to be adequate for the space I had but I opted for the larger heater just to have that capacity in reserve. I took inspiration for how to fold the corners of the polyethylene cover for the top from canvas artwork. There are lots of videos on YouTube showing how to stretch canvas tight and neatly fold the corners. It came out great. The Univent is amazing as it continuously monitors and adjusts the lid. It took a couple of nights with a hi/lo thermometer to dial in the right heater settings.

"I can't get over how easy this will be each spring from now on."

I REALLY hope that statement is true. Hopefully your set up is bulletproof. Do you have a generator, in case the electricity goes out? While extremely unlikely, what if the temps dip down to about zero? Perhaps you can run a test next winter on the coldest night of the year. It does look like you've well thought out and planned everything for normal conditions. Nature, at times, doesn't like to be mocked.

If you find any minor things that you believe could be done better, I'd like to hear about them. After close to 2 decades of seedlings in the raw, I'd like things to go a bit smoother, here.

And, with the right setup, perhaps I could experiment with "cold treatment" of peppers. The commercial vendor Johnny's goes into detail about that subject.

[Setec Astronomy]

Yeah I would love to see a pic of it. The univent sounds amazing.

One of my early threads here was about trying to fix my old Vent O' Matic cold frame. It never occurred to me (at least I don't think it did) that there might be a whole new opener mechanism I could get, although that could have been tricky adapting it. The Vent O' Matic turned out to be a little short for tomato seedlings, at least the leggy ones I was trying to put in there at the time. This thread jogged my memory about trying to fix it this year for hardening off seedlings.

Those Univents are available at Johnny's and Amazon has similar/same ones.

dalen-vent-o-matic-cold-frame-t918.html