What's their secret?
 

Plant farms like Bonny have great looking tomato plants at Lowe's. Their plants are bright green, stocky and generally look like the picture of health. My seedlings on the other hand pail by comaparison. The color is not bright green but a much darker green with purple on the underside of the leaves. I don't have a problem with tall spindly plants but they seem to get about six inches or so then the growth slows dramatically. I kept them under shop lights for several weeks then they went outside. Should I fertilize them. I have sprayed the a few times with a VERY light mixture of seaweed and fish emulsion.

[quote=BR;59322]Plant farms like Bonny have great looking tomato plants at Lowe's. Their plants are bright green, stocky and generally look like the picture of health.[/quote]

Commercial growers grow in greenhouses, and not under lights. They also generally grow plants at coolish temps (high 50's - 60's) which makes for stocky plants with a good root system. But your plants will be just fine too once they take off.

[quote=BR;59322]My seedlings on the other hand pail by comaparison. The color is not bright green but a much darker green with purple on the underside of the leaves. I don't have a problem with tall spindly plants but [B]they seem to get about six inches or so then the growth slows dramatically[/B]. I kept them under shop lights for several weeks then they went outside. Should I fertilize them. I have sprayed the a few times with a VERY light mixture of seaweed and fish emulsion.[/quote]

I'd fertilize with a 1/3 - 1/2 strength solution.

What Suze said about cool temp growing is correct.

My art studio is in a cool walk-out basement that is unheated except when I'm down there. So it's about 60 degrees most of the time. Yet it has two south-facing windows with big sills that are perfect for holding tomato seedling flats. Since growing in natural south-facing light in cool temps, my seedlings have really gotten "Bonny!"

At what age should they get their first feeding and how often thereafter should they be fertilized?

The dark green leaves seem to indicate too much nitrogen in there somewhere which also might account for the taller growth than normal, is the compost some of that multi purpose compost as its a bit higher in nitrogen that nessesary for tomato plants.

[quote=BR;59355]At what age should they get their first feeding and how often thereafter should they be fertilized?[/quote]

Depends. [SIZE=2](LOL, "depends" seems to be my [B]go to[/B] word for the day)[/SIZE] :P

Seriously, many factors involved. Some will say they don't fertilize seedlings at all. Others will disagree.

I fertilize. ;)

Some seed starting mixes have added nutrients, others don't.

I use the compressed bales of Pro-Mix, which really doesn't have much in the way of added ferts. My first necessary watering after seeds germinate is when I first fertilize. 1/3 to 1/2 strength seaweed emulsion.

Then I fertilize again after potting up to 4 inch pots. For that, I usually use something with lowish nitrogen and a high middle # (phosphorus) at 1/4 to 1/3 strength.

i only fertilize until after they go into their final destination in the ground. I raise my seedlings indoors and don't want a bush there. The room where they are is also around 60F (17C) and they do get artificial light (there are no sufficient windows, nor is the sunlight ok early in the year here in europe). The gardencenters offers 'other' plants than mine but my plant are doing more than well in my greenhouse now so I don't know they were disadvantaged ...

It depends if you are growing large transplants for a hot climate like Houston, Louisiana, So Cal, Florida, etc. If you are going to have 12" tall transplants in a gallon pot, you will want to fertilize with fish/seaweed emulsion at the 6" stage, otherwise the seedlings will "run out of gas".

Also, if you're in a cooler climate and weather turns bad, you might get delayed a week or two in planting and you don't want to transplant a "spent" plant.