When do I start tomatoes from seed in upstate NY?

– Posted in: Mailbag, Seeds and Seed Starting, Vegetables

This is a lettuce seedling, not a tomato seedling. But at least it's a seedling. Photo 2007 by Talitha Purdy

This is a lettuce seedling, not a tomato seedling. But at least it's a seedling. Photo 2007 by Talitha Purdy

A reader contacted Cold Climate Gardening recently to ask:

I live in area between Syracuse and Ithaca… near Cortland. I have tomato seeds–many different varieties. When should I start the seedlings to grow in peat pots inside the house? Is it too early? While I am at it…what else should I be starting? Thanks a bunch.

My name’s Talitha, and I’ve been growing vegetables for our family for the past several years, so my mom asked me to answer your questions.

Unfortunately, there isn’t a very quick answer for your question, because it depends on so many different things. I know where Cortland is, generally speaking, but even knowing your general location really isn’t enough, because micro-climates can differ so much. For example—I normally get one last frost in the last week of May or the first week of June–but people just 1 1/2 miles away don’t get cold enough for this last frost! This is because we live in a deep valley, and the hills on either side of us really funnel the cold air right at us. People at the end of the of the street are out of the valley, and they don’t have such extreme cold.

The Standard Advice

So the standard advice is to start your tomatoes inside about 6 weeks before your last frost date. For me, that would be starting them around the last week of April. You will have to count back from whenever you think you get your last frost.

Because tomatoes dislike cold so much, it has been recommended not to plant them outside until 2-4 weeks after your last frost. If I did that, I wouldn’t be planting them out until the middle of June or the beginning of July!!

Pros and Cons of Wall o’ Waters

Wall o’ Waters work quite well for mitigating situations like this, and you may find it is a good solution for you. For me, my garden is on a hill, and Wall o’ Waters need level ground to keep from collapsing. Because my last frost date comes so late and my growing season is so short, I start my tomatoes around the first of April, and pot them on many times. By the time I plant them out, they’re in gallon sized containers and have thick stems and are quite bushy. I could, I suppose, plant them out and cover them for that last sneaky frost (there are often weeks before that last one where it doesn’t frost at all), but since tomatoes don’t like cold and I don’t like worrying about losing all my tomatoes, it doesn’t seem as good an option to me.

It really depends

So with tomatoes it really depends on your last frost date, your micro-climate, how many times you would like to pot them on, and how much season-extending you would like to do. On the year I used Wall o’ Waters (with much effort, as I had to level every single spot), I planted my tomato plants into the ground in the middle of April!!! The Wall o’ Waters were quite effective at keeping them alive, but I can’t say I really noticed a significantly earlier yield for all my trouble.

Using Wall o’ Waters

My guess is that your last frost date is typically in the middle of May. If you had level ground and the inclination to use them, I’d plant your tomatoes outside, with Wall ‘o Waters, at the beginning of May. I’d take the Wall o’ Waters off about 2 weeks after your last frost date (I’m guessing around the end of May), after the nights have moderated and don’t get so chilly. That would mean starting your tomatoes inside around the end of March.

Using Peat Pots

However, I also notice that you were planning on starting your tomatoes in peat pots. Peat pots are meant to allow the roots to grow through the pot; they are not meant for potting on. If you want to grow your tomatoes in peat pots instead of potting them on to bigger pots, I don’t think I would start the tomatoes any more than 3-4 weeks before the last frost date. Otherwise, your tomatoes will get too big for your pots.

Start these seeds first

As for your other seeds, the first ones to start would be broccoli, leeks and cabbage. Leeks can be started the very first of all, as you want them to be strong seedlings by the time you plant them out—so you can start them two months or more before your last frost date, maybe around early March (or even earlier). Broccoli and cabbage can be started 8-9 weeks before your last frost date. Those are cold weather crops, so if they have been properly hardened off, they can be planted out before the last frost.

Cold Weather Greens

The next batch of seedlings to be started are the cold weather greens, like lettuce, spinach and chard. These can also take light frost if properly hardened off, but they grow faster than broccoli and cabbage, so they can be started about four weeks before last frost date. These can also be sown straight into the ground as soon as it can be worked, but that doesn’t work as well for me. First of all, I have a better and more reliable germination rate starting inside, and can use a lot less seed. Second of all, although my ground might be technically unfrozen, it is still very, very sodden, and seeds that are kept too wet for too long rot instead of sprout. So I start my greens inside instead of out. Peas, however, I have always planted in the ground as soon as I possibly can, but I try to make sure they are in a well-drained or elevated area, especially if we are having a very rainy spring.

Heat loving vegetables

Squash and cucumbers need only be started a few weeks before last frost date, or if you please, straight into the ground after any chance of frost. Although they appreciate a long growing season, they grow so fast it is unfeasible to start them very much ahead of time.

I hope that helps. If you have any other questions, please feel free to ask!

About the Author

Talitha spent the last few years doing an absurd combination of work and school, and found it wasn’t very pleasant. Now she’s doing work, school and a garden, and life is a little better! She also enjoys photography and hand feeding her ducks. USDA Hardiness Zone: 4 AHS Heat Zone: 3 Location: rural; Southern Tier of NY Geographic type: foothills of Appalachian Mountains Soil Type: acid clay Experience level: advanced beginner Particular interests: herbs, vegetables, cutting garden, cottage gardening

In the end, this may be the most important thing about frost: Frost slows us down. In spring, it tempers our eagerness. In fall, it brings closure and rest. In our gotta-go world–where every nanosecond seems to count–slowness can be a great gift. So rather than see Jack Frost as an adversary, you could choose to greet him as a friend.

~Philip Harnden in A Gardener’s Guide to Frost: Outwit the Weather and Extend the Spring and Fall Seasons

Comments on this entry are closed.

Farmer John March 6, 2009, 9:24 pm

I agree, milk cartons are much cheaper and easier than wall of waters. Just remember to take the caps off the plastic ones or you will cook the tomato plants on hot days without ventilation. I also plant tomatoes a few weeks a part in case I lose some to one cold snap, the others I’ve still got in the greenhouse will be fine.

Jane E. March 6, 2009, 4:32 pm

If you are planning to home-grow tomatoes this year, I highly recommend The Tomato Stake.


Its easier to use than metal cages or towers, stronger than bamboo sticks, and wont rot or splinter like wood stakes.

Happy Gardening!

Ro February 24, 2009, 9:46 pm

In the Feb/Mar issue of Horticulture, they have a great article on getting early tomatoes (which to me means in the summer, not the fall). Not only does he repot often, but he removes the lowest leaves and pots up higher on the stem to produce more roots. He prepares his planting spot a few weeks ahead of time by putting decomposing waste in the bottom of the hole to produce warmth in the soil, and then covers it with soil. He puts the plant out 4 weeks before last frost, surrounds it with 3 1 gallon jugs of water, and then wraps it with a cage covered in clear plastic (I have also seen people use garbage bags) where the top can be opened and closed.

I only use peat pots for transplants where the roots don’t like to be disturbed. You could pot it on, however, by putting the whole peat pot in a bigger pot and surrounding it with soil (yes, I have done this).

When growing under lights, be sure to keep the plants an inch or so away from the lights, otherwise you will get very tall, but very weak plants.

You can learn a lot lurking around GardenWeb forums. They have a forum on seed starting under propagation and one on tomatoes under vegetable gardening.

My understanding is that peppers and eggplant are more sensitive to cold than tomatoes – I usually plant my tomatoes at last frost date.

I live 2 hours north of Talitha, but have more moderate weather. Winter is just as long, however.

Talitha February 24, 2009, 1:42 pm

Mary S., I missed your comment earlier—If you have level ground, wall o’ waters aren’t that fussy. I would use them in a heart-beat if I had level ground. I know it seems intimidating to fill all those chambers, but it’s actually not too hard if you use the top of either a milk jug or soda bottle as a funnel. It would be easier yet if your hose could actually reach to your vegetable garden (which, alas, mine does not). I do have to say, though, that if I did use wall o’ waters, I wouldn’t put my tomatoes out in April again. Partly because I think it’s too early for tomatoes to really get going, but also because it’s too chilly to be messing with water in April.

MSS, I do think wall o’ waters would be good for you. We have the same situation in May. It is not uncommon for us to have a few glorious (or even scorching—Mom and I can remember a few Mays with 90 degree weather!) weeks in May, followed by a cold snap. The glorious weeks make you want to get everything in the ground, but hard experience teaches there will yet be at least one more frost. It’s hard to sit by and do nothing, and one is always tempted just to risk it. If the wall o’ waters didn’t want to follow gravity downhill, I’d definitely plant my tomatoes out in May.

I have to flat out ignore all advice about not putting seedlings out until night temperatures stay above XX degrees. It’s not at all uncommon for our summer night-time temps to drop well into the low 50s, and often well into the 40s. (This can happen even as they soar into the 90s during the day—-going back that whole valley thing. A rule of thumb I sometimes use is that our weather will be about 10 degrees more extreme–hotter or colder–than what is forcasted for our area.) There was one extreme year where I remember hearing my brother scraping the frost off his windshield on June 30th!! This is an excerpt from a letter I wrote to a friend in 2005:

Weather has become one of my favorite things to gripe about. Cadie has been keeping track of the weather. Apparently, we got our “normal” summer weather in April and May. We hit our first 90 day on May 11. Mostly for my own amusement (though you should feel free to feel amused as well), here is some pointless data entry, starting with June 1, our weather looks like this (I’ll highlight interesting points):

Highs Lows

88.6 44.8
91.6 50.2 Jump of about 50 degrees in 12 hours followed by a 40 degree drop.
84.8 51.1
89.8 56.7
93.4 53.3
93.4 58.1
91.6 54
99.4 53.8
94.9 63.2
—skip three days (unrecorded)—
97 assuming the unrecorded days were all in the 90s as well (and I think they were) this is 9 day run of 90 weather
88.9 69.5
84.1 65.3
71.3 56.7
71.5 48.6
65.7 55.4
75.1 50.6
89.3 49.5
89.3 50
82.3 54.5
86.4 38.5 lowest temp in June
92.7 48.2 50 degree jump in 12 hours
98.3 52.6And then drop 40 degrees, and then climb 50 degrees. . .
99.4 61.4And then drop 50 degrees, and then climb 50 degrees. . .
99.4 59.6
96.1 65
94.9 67.9
94.1 67.5
94.1 61End of eight day run of 90 degrees
81.2 53.5
86.4 42.7 coldest day in July so far.
92.7 54 50 degree jump in twelve ours.
88.2 63.9
86.8 67
79.2 65
73 62.8
78.1 60.5 (July 9th, butchering day)
91.6 53.5
94.1 52.6
99.9 64.3 Hottest day of the year so far
92.7 65
91.6 62.3
97 61.7
91.1 69.5
and today’s high was 92.7Eight day run of 90 degree weather

33 days of 88 or higer weather 15 days of 87 or lower weather (give or take 3 days) and about half of those nights were 57 or cooler.

I noted the nights at 57 or cooler, because some plants are senstive to weather cooler than 60 degrees. One book I read said not to plant out basil until the weather stayed about 60 degrees. If one interpruted this to mean the daily weather, than I did that. If this means the night weather, than I shouldn’t be able to grow basil (but I am). Another book stated quite firmly that an eggplant will sustain damage in any weather below 60 degrees. I’m not growing eggplants, but I hear most people group together peppers and eggplants and both being very picky. So I wonder if that is one of the reasons why my peppers are always stunted and hardly produce a thing? Personally, I like the cool nights. But maybe the plants don’t? Maybe I’ll have to try row covers?

Thankfully, that wasn’t a typical year. But if there is one thing our weather isn’t, it’s moderate. Hence why just about every type of seed I grow, I feel the need to select the one that is the most resistant to just about any weather sort.

mss @ Zanthan Gardens February 24, 2009, 11:53 am

Talitha, thanks for the guest post. I appreciate all the specifics you include even though I grow in a hot climate and my situation is almost the opposite of yours–with plenty of it’s own tricky problems. But I find it very interesting to read about what cold climate gardeners go through.

Austin hasn’t reached its average frost date yet (Feb 26-Mar 3) and we’ve already had 9 days above 80 degrees. My nursery says not to plant out tomatoes until night temperatures are reliably above 40. This week our temperatures will range from 50s-80s…but we started yesterday with at 32. Confusing for plants and gardeners!

Now you’ve got me thinking that the Wall o’ Water might be a good solution here. Despite our few freezes, we have a short tomato growing season because in summer the night temperatures are too hot for tomatoes to set fruit well.

LINDA FROM EACH LITTLE WORLD February 24, 2009, 11:32 am

I am not a seed starter or veggie gardener, but I just had to say what clear advice this is. And all the wall o’water info was very interesting. Even if I’m not going to necessarily try it, I like knowing what others are doing and why. I also have to say that mom is lucky to have such a knowledgeable gardening partner!

Talitha February 23, 2009, 4:08 pm

Hi, Ellen, just wanted to make a quick note—if you start your tomatoes inside 6 weeks early you must pot them on, otherwise you are absolutely correct—they become root-bound and stunted. They aren’t going to be happy in a little two inch by two inch container. If I didn’t have such a short growing season, I’d say it wasn’t worth the bother, but because my growing season is so short, I really do find it necessary.

(BTW, this post was actually a response to a question Mom got via email. She doesn’t do vegetables, so she forwarded the question to me. I’m always glad to give my best shot at answering questions, but I really don’t consider myself an expert.

Tina February 23, 2009, 2:26 pm

An even easier and customizable tool (for anyone’s specific area’s conditions). It will tell you exactly what and when:
The Grow Guide

Ellen Bell February 23, 2009, 12:08 pm

I’m also a vegetable gardener (not necessarily a very good one, but I still enjoy it!). Anyway, last year I started all my tomatoes indoors from seed. I followed the package advice, starting them about 6 weeks before the last frost, which in my area (Des Moines, IA) is about April 1. My tomatoes were so big by the time I was ready to move them outside, they were unmanageable! In fact, once I moved them outside, it took them quite a while to take hold and really start growing. I think because they got so big in their indoor pots, they were somewhat “stunted” and had trouble afterward. Anyway, my advice would be not to start things too early indoors!

Mary S. February 22, 2009, 7:14 pm

I agree with Susan about wind protection. I’ve never tried wall o’waters because I’ve heard how fussy they are to put together, but I put a bit of plastic or a cut-off milk carton around my tomato seedlings to keep them from fainting in the wind–which is also a problem in my part of Minnesota. Thanks for the good advice on seed starting.

Susan Appleget Hurst February 22, 2009, 3:37 pm

You’ve done a great job organizing –and describing– your seed starting in the spring, Talitha. I especially appreciate your comments on the Wall o’Waters; I felt the same about my results, and I also dream of level garden beds!
The earliest tomatoes I ever got were planted a week or two earlier than normal, but I think the thing that made the difference that year was that I put the cages in place immediately, and then wrapped the bottom 2/3 of the cage in row cover. It protected the seedlings from wind (can be a big problem in Iowa) and provided a bright, slightly warmer microclimate for them. I picked my first tomatoes on July 2nd that year.
The row cover was left in place until late July, when heat and humidity made the importance of good air circulation more critical.

Chiot's Run February 22, 2009, 10:53 am

Skippy’s has an online planting calendar. Fill in your last frost date and it will tell you when to start things. (http://bioarray.us/Skippy%27s%20planting%20calendar.html)

I like to start my tomatoes early so I can repot them and get them really big before planting outside. I have a covered porch I keep them on for a week or two during that in between possible frost time.