Greg,

What type of potting soil are you using? You should be a "soiless" mix (like Pro-Mix) so that you don't introduce soil pathogens to your seedlings. Are you using any fertilizer? The answer to this question should be "no" until you start to get true leaves.

smithmal

Make sure your light is as close to the seedlings as is humanly possible, and try having a fan blowing gently near your seedlings to encourage strong stems and maximize air circulation. Some people spray dilute hydrogen peroxide or chamomile water or other solutions that are designed to prevent damping off. I don't do much seed starting indoors for just the reasons you are facing, but I know many folk are very successful. I hope you can solve whatever the problem is. Good luck with your garden.

Martha

I agree with Martha, on possible causes.

damping off = = TOO MUCH WATER

I have successfully grown seedlings in peat pots using soil-less mix. I haven't grown them under lights recently, but am planning on doing that this spring, and I have read that 16 hours is the max that they need.

Rather than spritz the leaves (tomatoes don't like wet leaves and it encourages disease), I use a teaspoon, and give my little pots two teaspoons of water at a time.

I hope this helps.
Linda

It sounds like:
1. Too much water. Water less frequently. Forget the misting also.
2. Temperature is a bit high. I grow my seedlings at 60-65 degrees I too use a fan daily to encourage strong stem growth.
3. Little or no fertilizer until transplant stage. The seed contains enough food.
Good luck on your second round.

Yes. You are watering too frequently. Not to worry. It just means you're trying too hard. Water them well, then check them every three days until you find the right timing. For me, once a week watering is usually just about right. And definitely don't mist. In Houston, your humidity is going to be plenty high enough.

I don't know when your planting out date is, but six weeks before that is the best time to start seeds. Any earlier, and your plants will outgrow the lights and will get leggy.

I'm surprised your seeds took so long to germinate. Typically they are up in less than a week, sometimes as fast as three days. Some possible explanations could be planting too deeply, temps too low for good germination, and inadequate light.

Once the seeds are up, you do need to move them to a cooler place to grow on. You could try an unheated bedroom, or your garage in your climate. Just be sure they aren't out there in temps below 50 at night.

If you start over in the same pots, be sure to sanitize them in a bleach solution so you don't do the damping off thing again.

Thanks for all the replies and great advice! Next time I'll try less water and a fan if I can fit it in. As for growing medium, I used a bagged seed starter mix from Calloways. Regarding fertilization, I did none.

A few other things I should have mentioned earlier are that:

- Most of the seeds were packaged for the 2012-2013 season

- Many of the seedlings did emerge on or about the 7th day

- The bottle that I used to water with was previously used to spray a Neem oil dilution and although I washed it with hot water, traces of the oil remained

- Just tonight I noticed a single tiny little bug - about the size of a pinhead - fly away when I moved the tray

- The light wasn't applied until about the same time the seedlings emerged and was kept about 4 inches from the surface (due to ignorance and the popsicle sticks)

I'll start brand new trays in the next day or so and use what I've learned here. Given the consensus seems to be that I overwatered, is there a proven empirical approach to determining when they need water?

Thanks!

I have better luck with potting mix adding some extra perlite. I also had bad luck with seed starting mix especially organic Jiffy Mix. Nothing did well in it. Misting twice a day is what killed them though. I start seeds in my cool basement and 7 days does not sound too long to me. As long as they come up you are doing OK. I don't think there is anything wrong with your seeds,. I have mine under the lights before they come up. I don't like them going without light at all. I usually plant my tomato seeds too early. Last year I got caught because it snowed in May which is very unusual. My plants were too big for my lights. I think you can have pretty big plants though if you can get them in bigger pots as they grow. Where you live you want to get a head start on the heat because tomatoes won't set fruit when it is hot.

I just looked at your picture again. Are they in pressed peat pots? I think plastic is better for drainage. I use recycled plastic containers some that annual flowers came in the previous season. Although tomatoes need a bigger pot because they grow fast, I have found you can start in a smallish plastic 6 pack and move them to a bigger cup. The plastic small containers drain well and drainage is really important. Also the bug you saw was probably a fungus gnat and those come in the peat. They say watering too much brings them; I have had them too.

This post was edited by helenh on Thu, Jan 30, 14 at 12:06

If you keep seeds in plastic in the refrigerator, tomato seeds stay viable for several years. Your seeds are not too old unless they've been stored improperly (like in high heat, for instance). I agree with Helen about Jiffy Mix Seed Starting Mix. It's so bad that I refused to try seed starting mix for years. But last year, I bought a better quality and had great results with it.

Also agree about the peat pots. I have had lousy results with them. They wick water from the soil and then dry out bone dry in no time at all. It's very difficult to maintain proper moisture around your seedlings in them. Plastic or styrofoam works much better. (I am intrigued with Cow pots, but have no tried them. They are so expensive. Would love to hear someone's experience, though.)

I would keep the seed trays in the light from the beginning. Unless a seed says that it specifically needs darkness to germinate (like pansies or vinca), it's best to keep them in light. The instant they germinate they head for the light and if it's not there, they get leggy fast.

Yes. The gnats are likely moisture gnats. They are a pain and reproduce incredibly fast. You can get rid of them by putting a layer of sand over the top of the soil in the pots. They are another reason I grow my seedlings in my basement. (They are a nuisance, but they won't hurt your plants.)

Just a note, it's generally said here on GW that the lights should be on for 16 hours a day and off for 8. Plants need the rest. (like at night out in nature) It's easy to arrange this with a $5 timer attached to your fixture.

The comments about the peat pots got me thinking; it's perfectly reasonable to assume that if the humidity is low (and, believe it or not, it is right now in Houston... indoors anyway) then a peat pot could wick quite a bit of moisture. This is consistent with what I noticed. During the day while I was at work the pots would dry up quite a bit so I would water and the cycle would repeat overnight so I'd water again in the morning. It was a constant cycle of dry-wet-dry and it might have had something to do with their untimely demise.

I'll try a different medium and this time the light will be on the digital timer from the moment they're planted. I'm still interested in an empirical technique for determining when adding water is required, but also recognize that may just be a component of the proverbial "green thumb" that comes with experience.

Thanks!

Moisten your seed starting medium at the beginning prior to planting and then try watering from the bottom. It has worked for me for the past 50 years. The comments about light and darkness above are good ones to take heed of. I do not put them under lights until they germinate. Some plants need light to germinate but I do not think tomatoes are in this company. To repeat, a cooler temp in the 60s would be helpful for sturdy seedling growth. Gave up on peat pots during the Reagan Administration. They just don't work well for me. (No political statement intended). I have been growing about 20 varieties of hybrids and OPs for many years. Usually grow about 200 seedlings of which about 180 are given away to friends and neighbors. Great fun.Good Luck to you aand keep us posted.

I tried peat cells. Didn't like it. Why? Because, being so small, porous and the starter mix is also mostly peat, what do you get ? They are soggy when watered, for a while then get dry fast. For this reason I transplant from paper towel to 2 1/2" round or square plastic pots. They stay more consistent and manageable.