User avatar
grrlgeek
Senior Member
Posts: 162
Joined: Sat Aug 24, 2013 2:03 am
Location: Southern California Desert

Timing the transition from heat mat to lights?

I got all of my early-indoor starts going over the past two weekends. We are using a combination of leftover peat pellets (until they are all gone) and soil-less mix in soil blocks. As of today, I am starting to see little sprouts and I'm sure more are coming any minute from the first batch 8 days ago. (well, i hope they are anyway!). I have more than I know what to do with, but I am banking on beginner failures to cull the excess before I get them outside.

The question I would pose to all of you more experienced with starting indoors - is - at what point do you move the seedlings to lights? More specifically, do you hand-pick each start individually when it reaches that certain stage? Or, do you sort of wait for a batch to catch up to the early risers and move groups at a time?

The peat pellets are easy enough to move one at a time if, indeed, I should be doing it that way. However, I am a little leery of plucking one of those little soil blocks out of the middle of a group.

How and when do you do it, and what has worked, and not worked, well for you?
Zone - USDA 8b / Sunset 11

wolfwalker
Full Member
Posts: 16
Joined: Fri Jan 24, 2014 11:49 pm
Location: North central PA. Zone: 5A

Re: Timing the transition from heat mat to lights?

I start my seeds on heat mat under the lights but never turn on the lights until i see a couple seedling pop through. Then i turn the heat off and drop the light until just above the plants.I pot after all the seedlings have true leaves.I use jiffy pellets, cells with seed starting mix and speedling seed starter trays. My potting mix is MG.
Lettuce is the only plants i start under lights... Seems lettuce likes the light. My light system is T8 shop lights and T5 plant starting lights.

User avatar
rainbowgardener
Super Green Thumb
Posts: 25303
Joined: Sun Feb 15, 2009 11:04 pm
Location: TN/GA 7b

Re: Timing the transition from heat mat to lights?

I start all the things that need heat on the heat mat under lights, very crowded in little cells. Many small seeds, like a lot of flower and herb seeds, need light to germinate. Once they have true leaves, they are moved off the heat mat, under lights, to one per cell. Waiting until they all have true leaves, gives the slower starters a chance to catch up. When they outgrow the cells, they are potted up to 3.5" pots.

Not everything needs light to germinate, but all plants need light to grow as soon as they have leaves above the surface. If you are germinating them away from light, then you will need to move them under the lights right away. They will start failing within a day or so, without light. So you won't have the option of waiting for slower starts to catch up, you will need to move the first ones under lights right away.
Twitter account I manage for local Sierra Club: https://twitter.com/CherokeeGroupSC Facebook page I manage for them: https://www.facebook.com/groups/65310596576/ Come and find me and lots of great information, inspiration

User avatar
grrlgeek
Senior Member
Posts: 162
Joined: Sat Aug 24, 2013 2:03 am
Location: Southern California Desert

Re: Timing the transition from heat mat to lights?

rainbowgardener wrote:
I start all the things that need heat on the heat mat under lights, .........
If you are germinating them away from light, then you will need to move them under the lights right away. They will start failing within a day or so, without light.
Thanks for the good advice. Advise.... I think that's what one asks for when they already know the answer they don't want to hear LOL. I believe that I have to rethink my plans to germinate in the house and then move them to the garage. It gets down to the 30's out there at night.

Out in the garage we had rigged up a wire shelving unit, 36W x 18"D, with 36" fluorescent fixtures hanging on chains inside each shelf to receive the seedlings. It's easy enough to move, but I was hoping I could keep the operation out of my dining room. Reading your and wolfwalker's comments though, tells me I need to combine. I have an indoor plant cart with a mini grow light in the lower shelf and I put the tray with emerged seedlings in front of the best sunny window and 3" from the light for now. The consolidation indoors with the bigger fixtures will have to wait for the weekend though, so I hope they will be okay until then.

Thanks much for your sage wisdom!
Zone - USDA 8b / Sunset 11

Bobberman
Super Green Thumb
Posts: 2437
Joined: Tue Nov 16, 2010 3:31 am
Location: Latrobe Pa.

Re: Timing the transition from heat mat to lights?

If you do not give the new seedlings light right away they will get very thin and skinny and not healthy!
I enjoy fishing ,gardening and a solar greenhouse! carpet installation repair and sales for over 45 years! I am the inventor of the Bobber With A Brain - Fishing Bobber!

Return to “Seed Starting Forum”