General guide is 50s at night. Are they well hardened off already? if not they need to be. That will take about a week and by then the night temps should be consistently in the 50s, right? Otherwise you may have some nights you'll need to cover them..

Dave

I started from seeds around January 13th. I initially grew them under grow lights, but took them outside whenever it was sunny. They've been under the sun ~8 hours/day for the past 2 weeks.

Well, according to weatherspark.com the night time temps here will be 50úF or more starting April 21st. For this month the night time low is 48úF average. Is 48úF too cold for tomatoes/peppers?

Last summer, I was able to get my tomatoes and peppers out earlier than usual due to an early spring, but we still had some nights that dropped into the lower 50's. The tomatoes did fine, but information I've seen on peppers says that if they get below 55 in the spring, their growth could be set back significantly. Therefore, I would cover the peppers every evening with an empty plastic flower pot or frost blanket until lows were consistently above 55. This worked out for me.

So based on that, I'd say definitely no to the peppers at 48. They like it even warmer than tomatoes.

Air and soil temp requirements for peppers is very different than for tomatoes. Peppers prefer much warmer air and especially soil temps and can easily be stunted if planted too early.

As a general guideline peppers don't go into the garden until at least 2 weeks after tomatoes. So yes it would be too cold for peppers. And it is important to remember too that the recorded air temps and the soil level air temps where the plants are are very different. Official reading are done at 5-6 foot while the coldest air settles lower to the ground.

As for tomatoes. While they might tolerate the low-mid 40s they certainly won't benefit from it at all so why push the planting and risk their loss. If providing them with some protection is simply out of the question then wait to plant until the proper time.

Often folks start their seedlings far too early and find themselves in this bind so they are forced to transplant them into larger containers to keep them in the protected environment.

Ultimately it is your choice but why lose all the effort and work by rushing the transplanting.

Dave

With tomatoes, soil temp is more important than air temperature. Soil temps of 50 degrees are the bare minimum for plant growth in general. If your temps aren't 55 and going up, very little will be gained. Black plastic on the ground, and tents around the plants with red cellophane can get you going at this time of year.

I actually don't want to transplant them outside yet, but since they're outgrowing their current pots I'm considering it. In my case, I have 4/5 gallon grow bags. I don't know if I want to put them in grow bags that big just yet because the tomatoes are only about 10" in height. I think the best solution is to get 1-gallon plastic pots and just keep bringing the plants in/out of the house.

I actually do have a temperature sensor at ground level (or plant level). Last night the coldest temp was about 54úF, but a few days ago it was about 46úF. It probably is still too cold.

I believe the daytime temperature here is perfectly fine, it's just the night time temps that concern me. I think we have basil seeds sown in the ground that have already sprouted. Would that be a good indicator that soil temperatures are warm enough?

Agree that day temps are of little concern. It is the night temps that need to be heeded.

On the other hand soil temp is a much more valid indicator of transplant time than even night air temps. That is how many of us get away with early transplanting - covering and warming the soil to an artificially higher temp.

Tools such as WOWs, a clothe, even black plastic soil covering can back up transplant dates by a good 2 weeks when used correctly.

How many plants are you talking about? A few can easily be transplanted into things such as milk cartons, cut off pop bottles, plastic butter dishes, etc. with holds in the bottoms to gain time. Of course if you are talking about 50+ plants that is a whole other matter.

Make a note to start them later next year,

Dave

We do have basil and beans already sprouted from in dirt sowing, but we don't cover them at all. I think it's primarily due to the early warm weather we're already having, but it seems like the weather is slowly starting to cool again.

I think I've seen this term in another post, but what is WOW an acronym for?

I probably have 40-50 plants total, but need to transplant about 15-20.

The last frost date here was around 2/19. I've read that it's okay to start seeds about 6-8 weeks before that?

Here's a pic of my tomatoes in their 16 oz plastic cup containers.

Rather than transplant twice, I would get the bags ready, and let them warm up for a day or so and then plant out the tomatoes. The soil in the containers will be warmer than the soil in the ground, particularly if you cluster them together so that they form a heat retaining mass.

Though you are surely past the danger of frost in your zone, you could hrow a light cloth over them on the cool nights and that will keep your temps up.

Jan

WOWs are Walls o' Water plant protectors. They are sold by most all seed and/or gardening stores and websites.

Here is a link that might be useful: WOW's pics

The plants look real good to me. I would just pinch off the bottom leaves and fill the solo cups to the brim with additional potting soil. Then wait until you are sure of the temp before planting out.

I'll take some of that 70 degrees!

I'd check your weather history to determine average low temps. Soil temp can be improved with a mulch. I'd avoid black plastic though. It creates anaerobic bacteria and chokes the good things in the soil.

Some of that grow cloth would easily get you through the nights. However if you do create a temporary structure leave them in it before you place them in the ground just in case some really bad weather comes so you can still take them in the house.

I imagine after 2 weeks they are used to the sun which is good. They need to slowly get used to the moon if you will.

They look good but how many hours of sun light are in a day right now? 12. Tomatoes will grow slowly until they get more light.