What is wrong with my baby tomato plants?

Some of them have leaves that have very pale thin places on them...and some are just getting white spots. This is the first time I've grown them from seeds and I'm just now "hardening" them. I was wondering if it could be sunburn?? But I can't find any pictures of that!
I have 166 plants. Only a small portion of them have this...but if it's contagious...I need to know!

Thanks so much!
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[bcday]

Yes they are sunburned. It isn't anything contagious.

[noinwi]

Taking a little extra time to harden them off will help. Start them in the shade and gradually get them used to the sun and wind. I know it's hard not to put them in the sun...it seems that 's what they would need...but you have to protect your babies from too much too soon.

[OtterJon]

Yup, the gotta sunburn. If you started them indoors under lights, then go to harden off...Start in indirect sunlight near the house for only l or two hours...then gradually increase the time, and start adding more sunny spots for them to sit..finally when it's over 50 at night..leave em out all night..It can take practice starting from seed. The first year I did it, I windburnt my plants...hope all the others do great!

Jon

Will those recover if I put them in the shade for a while now?

[bcday]

The leaves that are not sunburned and any new growth will be okay. Just continue with gradually hardening the plants off.

The white areas on the damaged leaves won't turn green again. Those leaves will eventually dry up and fall off.

[FarmerShawn]

Yup, classic sunburn - I've seen it many times myself. Treat them gently, and they will recover just fine, with just a slight setback. As was already noted, the affected leaves will dry up and drop off on their own. I never sped that along by removing them, as I figured that as long as they might help the plant along even a little bit, they were better left on. The plant will soon outgrow those little, shriveled leaves.
Shawn

[nnjjohn]

I'm definitely no green thumb, I sure hardened these bad boys,, I mean big boys I guess it will be off to the flats come planting season

[lakelady]

I wait until mine have 2 sets of true leaves (after the first set, which are the cotyledons) before doing any hardening off at all. I think they are just too young and fragile any earlier than that.

Because my kitchen is so bright and sunny (southern exposure, skylights and sliding door) when I do harden them off, they do quite well with the real sun because they've mostly been getting a slightly weaker version of it anyway indoors. I'm not technical so I don't know anything about wattage or how strong indoor lights are compared to the real sun.

[OtterJon]

Just so you know Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux. Bright sunlight provides illuminance of approximately 100,000 lux or lumens per square meter at the Earth's surface. The total amount of energy received at ground level from the sun at the zenith is 1004 watts per square meter, which is composed of 527 watts of infrared radiation, 445 watts of visible light, and 32 watts of ultraviolet radiation....in other words....keep baby plants that just came from inside...out of direct sunlight for a bit....

[nnjjohn]

yes I know now what I thought I was going to avoid but was away and had my sister babysitting these.. she left them out too long.. I might have done the same same couple times before I left for the weekend, when I came back , they look worse! lol i guess i almost grew plants this season! alas, i want rutgers and ramapo plants too anyway.. should I get some of these to pull through, i 'll be happy with a dozen of these beefs and big boys.

[OtterJon]

If any of your big boys and ramapo are doing ok....keep em...youll still get a nice harvest...it's a learning curve for sure..been there myself..but starting from seed is very rewarding...you can get many more varieties from seed than from a nursery..those guys look very young and your in jersey...so decently far North that you can even start over now if you want....and I can send you any seeds from over 800 of my varieties if you want em...not a prob...I can pick some early varieties, so you won't miss out if youd like...I'm in Michigan and my plants won't even be out for a bit, as our weather has been nuts... just shoot me a pm

Jon

[nnjjohn]

otterjon, you are very kind generous person too, i get teary eyed when I read people trying me here lol.. seriously, I want to do this using the seeds I have.. i did start more seeds in the seedling jiffy tray .. going to see if i can get it right this 2nd attempt.. and not ditching those seedlings outside yet,, today was like 80 outside tomorrow will be warmer.. i've got time.. also enough variety.. my two beds grow plants without a problem.. two other beds have to get tested because i might have dumped too much or too little of whatever i used over the last few season. But I will check here for updates as well as post any thing new going forward,, best of luck up north my friend!

[guruofgardens]

I wait until mine have 2 sets of true leaves (after the first set, which are the cotyledons) before doing any hardening off at all. I think they are just too young and fragile any earlier than that.
-- I'm with you, lakelady. Usually by the time they have their 2nd set of true leaves, their root structure is developed enough to transplant.

I think I'm overprotective when it comes to hardening off the plants. I usually keep the plants outside starting with 2 hours, but out of the sun for the first week (!), increasing their time outside by an hour or two a day. They only get a glimpse of sun on their leaves during this week. Then they're ready for sun and overnight.

Good luck! It sounds like you've got 'the gardening fever'!

[nnjjohn]

When you folks mention taking them out for an hour or two or even four hours .. are you still using growing lamps indoors? I am not sure yet if indoor growing lamps apply here.