Barring any forecasted dips, it's time to leave the nest. Those temps are fine for transplants. Sometimes crap happens. But as seedlings cool temperatures are generally fine down to the mid 40's. If you are over 50 F in 10 days, flowering will be fine too.

In a perfect temperature controlled world there'd be no risk, but we're still not there. The question I have is if you've hardened the plants. If not do that by increasing mid-morning exposures for a week first! Then plant out

Good luck!

PC

Have the plants already been fully hardened off? It can take up to a week to do that. If so then you have to use your local weather forecast to guide you or plan to cover the plants in some fashion if the weather changes. Any idea what your soil temps are? That's the best indicator.

48 degree nights won't hurt them but if the soil temp is still lower than that they will just sit and pout. And a forecast of 48 degrees means it will be closer to 40 degrees down at their level.

Except for the 5 I have growing under cloches my plants won't go in until late next week down here so yeah, it seems early for you IMO.

Dave

We planted out Batch #1 today. We were facing the same problem. Our plants are large and needed to get in the ground. 42 plants. Zone 6A. Hardened off for 1 week. It's been in the 70s for several days. Soil temp is in the 60s. Our long term forecast is similar to yours. I don't like to see anything in the 30s. 40s and 50s for lows should be OK. Our daytime highs from 60 to the mid 70s.

Shell 6A

i am in CT (zone 7a) which is not very far from you and my tomatoes have been in the ground since april 10th. i am right by the coast so it's the warmest part of the state. this is the earliest i'v ever planted due the short winter we've had this year. i normally plant around the last week of april.. the plants are doing exceptionally well and have almost doubled in size despite the temp dropping to 42-45F two of the nights. i do cover them if temps are going to be dropping below 48-50F and i also use kelp (and as foliar spray) which may help the plant through cold/heat stress. but the covering at 48 isn't really necessary, unless it's very windy/rainy.

if you can provide cover for them in case there is a late cold spell where temps will drop under 40 then go ahead and plant them, but i'd say that is highly unlikely. the last time we had frost was very early march. days temps have been between 60-70 with a few mid 70s days.

Do you find florescent plant lights tend to make the plants look yellower than they really are? I can't tell if the new growth on my plant is yellowing, when the grow lamp is off they look green. under the lamp they look yellow

Google what the average last frost date is for your area, and then look at the long range forecast.

Be careful about "average last frost date". That means that on that date there is a 50% chance of a freeze afterwards. Most recommended plantout dates are several weeks beyond that.

The conventional wisdom here in central Maryland is Mother's Day, but next weekend is supposed to hit close to 90. If it looks warm after that as the forecast develops, I may take a gamble and plant them next weekend.

In my climate, tomatoes are not recommended to be planted out until June 1. It has little to do with night time temperatures but everything to do with soil temps. Unless the soil temp is 55F or above, the plants will, as Dave described, just sit there and pout. No root extension or top growth. If that is combined with generally cool air temps and a lot of rain, the plants can actually kick off and die.

The PNW soils tend to be very slow to warm up in spring, likely due to our very northerly location and generally cool springs and early summers. Last frost date here is end of March, so that is not a concern at all.

We've very temperament climate in the high deserts. I find this most useful.

Lookup your first and last freeze/frost dates by zip code

>In my climate, tomatoes are not recommended to be planted out until June
1. It has little to do with night time temperatures but everything to
do with soil temps.

soil temps do not take long to go up.. a few 60-70 degree sunny days will quickly increase soil temp, and unlike air temp, soil temps are stable once it warms up. i usually put a black tarp over the ground a month before planting to get an even earlier start. the night time temps play a bigger role than soil temps once your day temps are already in the mid to upper 60s, it's really all about night temps since the soil would already be warm enough.

your June 1st plant date is more related to all the rain the PNW gets in the spring, at least on the coastal areas which tend to be a lot warmer = earlier planting dates.

another thing about last frost/plant dates is they are outdated.. it's based on over 30 year averages.. over the past 10 years or so the climate has changed and it's safe to say that winter is no longer as long, or as brutal as it was 20+ years ago for many placers which makes last frost/planting dates almost useless to follow.

Using Millwood and White Plains, and checking their weather forecast, it looks like you hit mid 80's one day and have had several days in the 70's over the last few weeks, and no freezes. So if that is your mild coastal climate, verified by the April weather history in those towns, near the Ocean and Hudson, Wednesday next week looks just right for planting out. You need to condition the plants, so you have barely enough time to meet your plant out date especially as big as they are. (If that's the Westchester (???) in which you live.) Good luck!

PC

Thanks everyone. Tough for me to harden the plants as I'm away from the house weekdays. I'll get them all outside for a while both days this weekend.

"your June 1st plant date is more related to all the rain the PNW gets in the spring, at least on the coastal areas which tend to be a lot warmer = earlier planting dates."

I live less than a block from the beach so about as 'coastal' as one can get in this area without pitching a tent on the sand!! It still takes that late in the season for it to be suitably warm enough to plant out warm season crops. And it doesn't have much to do with rainfall either, as rain shadow areas of the PNW - very dry year round - still have a late planting date. It is ONLY related to cool weather and our very northern aspect.

It also depends on the soil condition as to how fast it might warm up. Light, fluffy, well amended soils and any raised beds will heat up faster than heavier, clay based soils. I'd suggest one use a compost thermometer to accurately measure soil temps to determine when is the best time to plant.

If the choice is between plants getting stunted and pouting in their pots vs. sulking in soil that's a little colder than they like for optimum growth, plant them out, IMO (after hardening off of course). I'm very familiar with weather around Westchester, and if I were you, I'd plant out.

The mid-Atlantic/NE coast is not like the PNW. There's no stretch of moderate weather between seasons. One day it's winter, then we have some weeks of wild swings back and forth between unseasonably cold and unseasonably hot with a surprisingly small percentage of days that actually are the average temp for spring, then suddenly it's hot.

I wish we had that extended moderate period in spring and fall that you get in some parts of the country, honestly, because even though it can make you impatient to put tomatoes in the ground, it would make it easier to grow crops that like moderate temps.

heroes1967: Thanks everyone. Tough for me to harden the plants as I'm away from the house weekdays. I'll get them all outside for a while both days this weekend.

Use shade cloth. Several layers. Every couple of days, remove a layer.

I have a bunch of old window screens I use. I stack three of them. Then remove them one by one. Plants harden off easily that way without needing a lot of fuss and monitoring.

The only thing you really need to worry about is setting up something to act as a wind break if a dry windy day is forecast, especially if temps are cool AND windy. In my experience, cool temps + dry wind will burn plants pretty catastrophically and much worse than sun.

I've seen this image repurposed for "spring in Ohio", "spring in NYC", as well as "spring in Canada". Sadly, it's one of those cartoons that has been completely appropriated by the Internet, and I can't seem to find information to credit its creator.

But I think a lot of West Coasters don't really get what the change of seasons is like in a lot of the US east of the Rockies and north of the Mason-Dixon line.

I planted out with temps hovering around 65/42 this year. Probably a little early, but the 15 day forecast says the same thing for every day, and the plants were getting unruly inside. The volunteer tomato plants from last year are coming up, so i'm thinking it must not be too cold.

Forecast shows nighttime temps getting as low as 48 degrees this weekend. After that, looks like mid 50s and higher.

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If those temperature are reliable, that is perfectly fine for tomatoes and peppers. Provided ( as Dave pointed out ) Your plants are already hardened off.

Also, as NC suggested, find out when your LFD is. And then check the extended forecast. And then make a move based on those data.

CASE IN POINT:

Just this year (early April), we hit a low of 35F. On top of that we also got a frost. Nothing happened to my tomatoes (50 + ) and peppers (25 +) but the eggplants got frost bite but they survived.

Sey