From everything I have read - t-5's are the best. However they are also expensive and if all you are doing is starting seedlings to plant out - probably more money than they are worth. Most people on this forum use inexpensive standard fluorescent shop lights that cost between 10 and 20 bucks a piece.

Agree that they are better but they aren't enough better than T8 IMO to justify the higher cost just for seed starting. I'll wait until the fixtures and bulbs are more reasonably priced to upgrade to them.

We all got along just fine for decades with the old T12s but as they are being phased out the T8s are the logical choice.

We have several discussions running here about them vs. T8s just a bit further down the page.

Dave

I've tried both and much prefer the T5's. I stress prefer purposely because I was able to start seedlings with the T8's. But, no surprise to some, I think the T5's are more effective.

Think extra light in the same space for less power. No leggy seedlings, no need to keep the fixture directly on top of of the plants. More air movement due to more space under the lights. Less stress on the plants - think better light penetration to the lower leaves of taller plants - no phototropism due to insufficient light.

One warning - the t5's get hot. You in fact can't keep the light right on top of the plants. Do so and you will cook yer babies.

Now, I started seedlings for years with a dual T8 fixture. The seedlings were usually leggy - despite having the light low and a fan on the side blowing over the flat. Unless I got them outside under stronger light after the second or third sets of leaves, they were inevitably tall and thin. I live in the Chicago suburbs. Getting them out early is not usually an option.

So, it made sense for me to get the stronger lights. Pricey, but I'm happy with them.

I start just planted under t8s , once I get the first true set of leaves I move them under t5s. To me the comparison is night and day.

last year I was able to grow tomatoes with fruit under the t5 set up, no way this could be done with t8s, that being said for many years I have used a stoplight and fan and gotten adequate seedlings.

For me the I have already gotten the value out of my t5s by growing through the winter , but if I only wanted seedling I would stick with a t8s.