Any pictures?

Hi Anne - Could you tell us where you live or what garden zone you are in please? You know it can be added to your log-on so that it automatically is attached to each post. That would be a big help. ;) Also, how big/old are these seedlings?

Since you are already hardening off I'll assume they are several weeks old, ready for the garden size, and that you are way, way south say zone 8 or 9?

Hardening off can be difficult, especially if one tries to rush the process and the young seedlings get exposed to either bright sun or are enclosed in such a fashion as to trap heat and have inadequate air circulation. In the shade and in the open air while shielded from wind seems to work best.

Under a plastic tunnel, 60 degree air quickly tuns to 85 or 90 degree air. If there is moisture resting on the leaves, they get scorched, the soil quickly dries out, and the plant's response is to curl and droop its leaves to try to control transpiration and retain moisture. Seedlings that are over-crowded and seedlings that have recently been transplanted are even more susceptible to quick damage because of the lack of adequate air circulation and adequate root development.

But they will usually recover with some TLC - out of the sun, increased air circulation, and cooler temps. How soon do you plan to transplant these to the garden? 40 degree nights might be pushing it a bit. ;)

Hope this helps.

Dave

Dave knows his toms.And his info.was good,but you did not say if you are watering with plain water or fertilized water, The reason I say this is because ,miracle grow potting soil has small amounts of fertilizer all ready in it,and your description sounds a lot like over fertilization.

You could have a windburn issue also, Takes a couple days to show. Any wind a few days ago while they were out?

Hi (I composed this on Word and did a cut and paste to post here before reading all of the posts - to respond to those more recent posts.... the plants are protected from wind and get regular tap water)

Dang! I just composed a long post in response and my computer crashed on me - so I'll try again. I think I'll try to be more brief and too the point this time so I can at least get a post off!

I'm in zone 8 in Merced, CA in the San Joaquin Valley of Central CA.

I haven't quite worked out posting photos to the list yet, but I'll work on it (long story)

My plants are in an elevated "salad table" - basically a raised bed on stilts with 8" high solid sides and a screened bottom. I've put cardboard down over the screen bottom and have cut up a couple of hula hoops (purchased for my bean trellising system - but that's another story) to support a hoop house type of thing.

I started my seeds on Jan 19 and have repotted twice. Just ran out and grabbed a typical plant to measure. It's an Earl's Faux in an 18 oz cup. Cup height 5," plant height above soil level 5," greatest "wingspan" 10" (!!!), and stem thickness 1/4." It was actually so beautiful, I had to give it a little kiss after doing all of the measurements :) It's not one of the affected plants, but is a beautiful, lush green. All of the other plants are of a similar size and vigor (except for the curled leaves). The plants with the curled leaves still look good overall, but I'm worried that if I don't remedy the situation, things could get worse.

I went out again and noticed some small burn spots similar to what someone else posted recently, so I think the problem might be sunscald. The low tonight is 43, so I'm thinking I might just leave off the plastic hoop tunnel thingy, so I don't have all of the dew sitting on the leaves . PLEASE let me know if this is a reckless thing to do - would HATE to loose all of my seedlings!

My raised beds aren't quite ready so I don't plan to transplant into the garden for another week or two. But the local stores are now selling tomato, etc. 6-packs for planting directly in the garden, so I don't think it'll be too long before it's safe to plant.

Thanks for the responses and looking forward to more!

Anne

I think that plants to be hardened off should be at, or almost at, transplant size which for me is from about 5-9 inches tall.

And once they are put out I think they should stay out rather than taking them in, taking them out, or coddling them under a hoop house. Of couse I'd move them to shelter if heavy rains or high winds are expected and for sure if frost is predicted, or any time the temp is roughly below about maybe 38 degrees, or so.

Hardening off should take only about a week after the transplants are taken from the house, them moved to a shady spot for the first couple of days, then into filtered sunlight and then finally into full sun.

The damage you describe could well be windburn as timmy mentioned or sunscald as someont else mentioned.

The whole purpose of hardening off over about weeks time is to expose the transplant size plants to the rigors of the outside. ( smile)

Carolyn

I sure wouldn't remove the tunnel for tonight. But then I wouldn't leave them out at 43 degrees either. ;) It's one thing for established plants, in-ground, to tolerate 40 degrees but it's something else when you're talking small seedlings.

But it isn't the dew sitting on the leaves that is the problem, it's the sun exposure coupled with the trapped heat in the day time. I'd bring them inside but if you want to leave them in the tunnel protection at night then move them to the shade in the day when it's warm enough, fine.

I don't know what your correct planting date there would be - perhaps others from the area would. But my gut instinct tells me you are rushing it a bit. Just the fact that plants are being sold locally isn't a good indicator that it's planting time. ;) They anticipate the season and plan for losses.

What are your soil temps? With nights that cool I wouldn't expect soil temps to be near warm enough and into the needed 50-55 degree range. When is your last frost date? According to Sunset, Central Valley can be frost as late as mid March. Sound right? If so, then planting would be a week to 10 days after that.

Just some points to consider. Good luck with them. ;)

Dave

Hi Carolyn and Dave,

Thanks for the info (although it's a bit conflicting). I decided to run out and put the plastic over the hoops, but I just tacked down the ends and didn't enclose things tightly. I have been removing the plastic in the morning so they're never under the plastic during the day.

I just moved to Merced in late Oct, so I'm not real familiar with the area yet. I think the last frost date is around Mid-March. I'll have to do a check on soil temps tomorrow.

The seedlings aren't all that tall I guess - 5" above a 5" cup so maybe 10" total, but they are VERY husky compared to all of my previous years with seedlings (not all that many -maybe just 6-8 years, but I've got some experience).

We did have alot of wind a few days ago, but the damage just showed up today. So maybe it is wind damage, combined with a bit of too much sun.

Of the two opinions (Dave's to bring them in at 43 and Carolyn to leave them out - once they're hardened off - down to 38), I'm inclined to go with Carolyn's advice. Other than the windburn/sunscald, they all seem to be doing great. I'm only planning to plant one of each variety and I have extras of everything but German Head, so maybe I can take a slight chance, but I'll keep my eyes on things. It supposed to be cooler this coming week - down to 38 a couple of nights, I think - so I may bring them in. But I'm wondering if I can add a couple of degrees to the outside temp if they are in the hoop tunnel? (Not really a tunnel as the ends are closed off).

Anne

Carolyn and I were writing at the same time but we are basically in agreement. I had misunderstood and thought you were keeping them in the "tunnel" during the day as well. Sorry about that. But we are both talking about bigger seedlings tolerance too - bigger than you have. The seedlings aren't all that tall I guess - 5" above a 5" cup so maybe 10" total Noooo, :) the seedlings are 5" tall - only the growth above the soil counts.

Main difference is that I wouldn't have started the hardening off process nearly as early as you did. Like Carolyn I only harden off for a week or so and only do it to 8-10" transplants that weren't recently transplanted. But that's just me. ;)

If indeed your last frost is mid-March then "technically" you still have a month to go before planting. Push it if you wish as long as you have back-ups. I got badly burned just last year even tho I had waited for the required 2 weeks after my frost date. Adding another week to it this year. Less stress for me AND the plants. ;)

Dave

Hi,

A PS - just wanted to add that I wasn't particularly trying to harden off the plants for transplanting when I first started setting them out. It was mainly because we were having great weather and I thought the fluorescent lights were sort of "cramping their style." Didn't want leggy seedlings and easier to set them out in the sun (gradually, of course ), rather than trying to up the indoor lighting. As I said, I don't really plan to transplant them into the garden for another week or two.

Anne

Hi,

I finally got a couple of photos posted to photobucket - here are the direct links:

http://i74.photobucket.com/albums/i244/annemw/2008_0301Image0016.jpg

http://i74.photobucket.com/albums/i244/annemw/2008_0301Image0012.jpg

The first photo is the leaf condition of a NAR and the second photo is my salad table with the plastic covering.

I'm thinking that the problem probably is wind damage. I recalled having pretty strong winds several days ago. It's been windy today (10-20 mph winds) and will be cool for the next couple of nights, so I decided just to bring them back in under lights for a few days.

I took the temp of one of my raised beds today - an instant read meat themometer pushed all the way in (about 6") and the soil temp at 7am was 60 degrees (air temp was around 50 degrees).

The NAR was probably the worst affected plant, and I have a feeling it'll recover fine as long as it's wind or sun damage and nothing more sinister.

Thanks for all of the comments and advice. I feel better now :). BTW, I noticed that some of my plants are developing buds - guess I should start plucking those off.

Anne

Anne,

I have to admit that I do the same thing. I take brand new seedlings outside ASAP when the weather is warm and sunny, since they'd be in the sun if they germinated outside as in winter sowing. I put them in a spot that blocks off heavy winds, though breezes flow through, and the sun hits that part of the deck only about four hours a day right now. It grows longer as the sun creeps northward.

I bring them in at night when the temps are going to get below 50 and leave them under lights if it's overcast or cold outside during the day. Fortunately, I have only three large flats of seedlings, not just tomatoes, and it's easy enough to bring them in and out. I just think they're healthier under natural light as much as possible. By the time they're set out in the garden, they're well-hardened and sturdy.

This way of handling seedlings isn't to everybody's taste or liking, of course, but it works fine for me, even if they have to miss their playtime outside because I'm gone for a weekend or there's a cold stretch of a few days. The physiological strengthening of the seedlings by being outside in the breezes and natural light is not lost when they're brought inside for a couple of days.

My confidence about handling the seedlings this way is based on the information in the link below, which is the best description of what hardening off accomplishes for the plant that I've ever seen. Actually, it's the ONLY description that I've seen. It is not a simple matter, but the more you understand about what an indoor-germinated plant experiences during hardening off, the more sure you can be about what you're doing by exposing them to the "real world".

Here is a link that might be useful: Bracing Up: Hardening Off Transplants

Hi Anney,

Thanks for the link. Very interesting!

I've pretty much read all of this info before, but not sure if it was all in one place. I think that the FAQ on this forum on hardening off (think it might have been a FAQ on growing from seed) is pretty good, although not quite so detailed.

I suspect that alot of the differing opinions on the hardening off process and transplant size might be due, at least in some part, to "zones." Those with a later last frost date and shorter growing season might want the larger transplant size and a briefer hardening off period, whereas in zones with longer growing seasons, the smaller transplant and more prolonged hardening off might work out OK. But then again, I might just be rationalizing what I'm doing LOL!

Anne

Yea,

That wind will get you every time. When you said something about "white" on the leaves all of a sudden that is.

Yes, it shows up a couple days later every time. You need about 48 hours of fairly calm weather to harden them up.

Hi Timmy1,

Thanks for your input! I'm relieved that that is all it is (rather than some disease or definciency)and feel pretty confident that all the plants will recover and that I can avoid having this happen again. For some reason I guess I equated "fans on your seedlings" (as a good thing) with being outside in the wind. Live and learn!

Anne

Hi Anne!

Since we're in the same town, I took my soil temperature tonight (9:00) p.m.. I used your same methodology - meat thermometer pushed all the way in. I took it in two different places in my yard, in two different soil types, and got the same temp you did - 60 degrees. So, soilwise, it would seem we would be o.k. to plant, but we still have until the middle of March for frost threats.

However, I feel that the frost is over for this year, so you might go ahead and plant anytime as long as you watch the weather and protect if necessary. I have planted as early as Valentine's day with protection, but I don't want to worry about missing a little nip. I planted mine last year the first of April and they did quite fine.

Elaine

Hi Elaine!

Thanks for posting your soil temp readings, etc.

I think I'll aim for about 2 more weeks before transplanting (and be prepared to protect them overnight if we suddenly have a spell of bad weather). That might be a good time to get together :).

It'll probably take me two weeks to finish up my raised beds for the tomatoes (have been working on the beds for cabbage, peas, leeks, etc.) So the timing should work out about right.

(Off topic - but gorgeous gardening weather today! I transplanted 48 mini-cabbage plants (3 different varieties) and got a good start on preparing my beds for my pea, broccoli, and swiss chard transplants. Tomorrow I plan to finish those beds and "pot-up" my peppers and eggplants to larger containers).

Anne

Hi,

I brought my plants back inside under lights last Saturday and they've been doing fine (my 5" tall Earl's Faux is now 7" tall and other plants are now 10" tall).

I'd like to start keeping them outside again - mainly to free up space under my lights in the house. Until the wind damage and cooler nighttime temps that caused me to bring them in, the plants had been gradually hardening off for at least a week. I was wondering if the physiological effects of that hardening off period had lasting effects, so that I can go straight to keeping them outside now (given OK temps and wind), or do I have to go through the hardening off process again - putting them out for a couple hours at a time to begin with, etc.

Thanks!
Anne

Though I've read that plants don't revert to their unhardened-off state if you have to bring them in for a while, I'd still err on the side of caution (since they've already been shocked once) and treat them as though they hadn't ever been outside.