petunias from seed not growing

I have planted some petunia seed. Most of them have come up very well. They seem to be just sitting there, not growing. I have some that have been up for almost 4 weeks and haven't seemed to grow at all. I have them under lights, try not to let them dry out and not be too wet. I have started turning the lights off at night for about 6-7 hours. The room cools down to around 67 degrees at night and is 75 during the day. I have started alot, but am getting a little discouraged at the non-growth.
Any help is much appreciated.
Thanks, Marie

The lights should be on from 12 to 16 hours a day and be from 2" to 4" away from the plants. Use a half strength fertilizer on seedlings that have at least two true leaves. In my experience, petunias are just slow growers. I started mine 3 weeks ago. Some are larger than a quarter while some others of a different color are still just starting to germinate.

I have done all that. I wish I could say that mine are even getting their true leaves. I will keep watching though. I have planted so many seeds that I don't have anywhere to put my new ones. I wish I had my greenhouse up and running.

What kind of soil mix did you use? Also, which varieties did you seed? Did you start out with the lights on for 24 hours and then changed to 16 hours on?

Joanna, I use Gurney's Seed Starting Mix. I used it last year with great success. I don't think that I am doing anything different from last year. I have started several different varieties of petunias, wave, double cascade, they sprouted but have not grown true leaves. I have the lights about 3" - 4" above the flats. I left the lights on for 24 hrs a day the first 3 weeks then have been turning them off for 6 hrs during the night.
Other seeds that I have started are doing fine for the most part. I have potted up my black eyed susan vines and my dahlias are getting their true leaves and growing like mad. I just planted them a couple of weeks ago. I finally have some brugmansia coming up. I had 32 of my hardy hibiscus come up but at least that many that have not even germinated. I have a set-up with 18 4' shoplights. I have changed out some of the bulbs, not all though. I have a cool and a warm light in each one.
I thought that the lights may be keeping the room too warm, that is when I started turning the lights off at night. The room gets 75 - 80 degrees when the lights are on. at night the temp goes down to 68 - 70.

I love the pictures of your gardens. I had thought of sending you a D-mail, so I am very glad that you saw and replied to this thread,

Thanks, Marie

These are some of the petunias from last year.

The yard on the other side of my flower garden is mine also. I bought the hours last year. I gutted the yard of the old ugly trees and will landscape it this year. I am very excited. That is one reason I am trying to plant so many seeds. I will be sending pictures as the year passes.

This message was edited Feb 26, 2012 1:21 PM

My guess is that you kept the lights on for 24 hours and it screwed up their internal clocks. Most petunias are daylight sensitive, and the seedlings may be in a semi-dormant stage now since they started with 24 hours and their day has become short now. It may take them a while to get going again.

I would not recommend having the lights on for more than 16 hours, ever. Although some seeds are recommended to be surface sowed and require light to germinate, this doesn't mean that they can do without night time. Many plants grow more at night than day. I'm not a horticultural expert, but I would guess that the plant does it's photosynthesis thing during the day and then at night it grows. Also the cooler temp at night is good.

Another possibility is that you got a bad bag of soil, but if your other plants seem ok, then you can probably rule that out.

Thank you Joanna. I just seeded some more, I will see what happens.

MyRee
Hi
What about adding some air movement like an indirect fan. I have found that having some good air movement helps. I just point it at the ceiling and not at the plants when they are really small.
Alberta Ann

Thanks for the tip. I will. Thanks.

MyRee, please keep us updated on the petunia situation. I hope it works out for you. I just post some pics (mostly of petunias) here: http://davesgarden.com/community/forums/t/1244166/

I looked on the link and am very envious of your planters. I love them.Thank you for sharing, it just makes me want to do better. Did you plant all from seed?
Please post the varieties of the petunias.
I have just about decided to try to grow the "easy" annuals - starting them from seed inside, and broadcasting petunia seed in the flower garden. I have so many ideas for baskets. We will see how they work out this year.
I started feeding my seeds and seedlings with 1-1-1 fertilizer. It is a seed starting mix and hopefully it will add what they are missing.
My dahlias and asters are growing like weeds. I have lobelia that is sprouting and some of my petunias that I planted a little later are starting to get true leaves.
I feel like it it is getting a bit late to start some seeds.
I ordered 12" hanging baskets and have made some out of chiclen wire. I have begonias in some of them and will plant lobelia with them.
I just don't have enough room for what I want to do!
Marie

I don't deadhead anything, so I choose petunias that are "free-flowering or continuous".
My list for petunias from seed are:

Tidal Wave: one plant in a 14" planter and that's it. Needs lots of root space. These are Big plants. They also sprawl in the flower bed and will grow up a trellis about 4 feet
Easy Wave + Wave + Shockwave. I use these in mixed combo baskets, window boxes & planters. None have great height and they drape, so if you are going for a ball look, don't use Waves. Easy Wave are less daylight sensitive than Waves, so they wil continue to produce flower buds as the days get shorter. These need lots of root space
Opera Supreme Pink Morn. Lots of blooms Tri-colour pink, yellow & white. Seem to have more height and more flowers than Waves. Considered a spreading petunia. I use them in window boxes
Limonchello from T&M. The best yellow spreading petunia from seed. Strong colour and free flowering. I use them in window boxes.
Ramblin' (Burgundy Chrome for sure): Best true white. I use these everywhere. Unique colours, considered spreading, more height than waves, not as long stemmed
Avalanche (Grape): Very cool colour. Smaller plant than waves. Stands up in rain well.
Dreams: Upright with big flowers. Great in flower beds and planters. Not suitable for hanging baskets. Free Flowering.
Sophistica Antique Shades: Upright big flowers. Flowers change colours with temperature, stronger with cool temps

My favourite vegetative (no seeds): all free flowering

Supertunia Vista Fuchsia and Bubblegum. Not all Supertunias grow the same. I like the Vista series because it will grow into a 4 foot ball-no side planting. I use 7 plants in a 20" HB
Potunias: Love the colours. Papaya (orange) did very weel in a grow bag with bacopa. Potunias have good height and are considered mounding. The stems grow about 15" long, so no 4' ball, but very nice in a planter, mixed hanging basket or windowbox.
Sweetunia Hot Rod Red: The BEST red. Good in all containers or hanging baskets

So, those are my "staples" every year. Of course I always try new ones and or colours.

Rule of thumb for # plants per basket: 5 -6 for 10", 6-8 for 12", 8-10 for 16". If you are doing all petunia, use the smaller #. If you have a combo of plants, use the higher number
Picture:
Tidal Wave Hot Pink in the black urn planters by table (1-plant per)
Supertunia Vista in the big ball by door,
Opera Supreme Pink Morn, Lemonchillo, Blue Easy Wave in the window box
Other in the containers & flowerbed
Note: Photo taken September 19th (leaves on the trees have started turning colour and we are well into fall in our area. Petunias are tough and will handle light frosts. Feed & water them and they will put on a show the entire season.


This message was edited Mar 3, 2012 10:12 PM

WOW. Thanks for the information. I may have a beautiful garden yet.
When do you start your petunia seeds?

Wow Joanna. Those are some mighty pretty petunias and baskets. From seed!! My petunias bloom better in all seasons other than summer so guess they do not like our heat and do so well in your northern temps. I will look for some seeds now.

Joanna, So beautiful.
The information is priceless. Thank you so much.

Petunia from seed is down right frustrating! Don't feel alone. Case in point. I've tried the winter sowing method in milk jugs, and recently tried starting them in South Florida for my mother. Great weather and conditions. Dismal failure though they could have dried out one or two days. Perhaps too much heat..side of house.

Yet look at this area at that reseeds every year in the driveway! They go bananas! It would look bushier had a I not transplanted about two dozen. That leads me to think about growing and seeding them in this type of soil? It's down right dry too yet they flourish!

Started this tray mid January in SW Florida. Three survivors out of 200. I did have eight at one time. Some kind of seed starting mix that consisted of coconut shavings. Sounded great at the time.

I give up...time to try NCFarms plugs



This message was edited Mar 6, 2012 8:12 AM

I too have had a difficult time with petunias. This is the third year I have tried. This year I finally had some success. My silver tidal wave petunias are big and healthy! I used jiffy pot pellets. (I have used miracle grow soil, jiffy soil and burpee pellets in the past) My best outcome is with the jiffy pellets. I think petunias really hate being too wet, and this medium helps that. Now... when I see the roots coming thru the mesh, I know I need to repot up to the 2" pots.. and I pull off the mesh before I do this. (The mesh really doesn't dissolve and it can inhibit root growth - in my opinion) All that said.... there is lots of good advice above as well... but this is what seems to work best for me... I have moved "Petunias" to my NOT SO EASY list of annuals to start. good luck

I started fertilizing more, watering less, and turning the lights off for at least 8 hours a night. I put them out into my little greenhouse and they took off. They are not as full as the pots for mothers day at the stores, but, they will be. I am loving this spring. Now, If I could just have more hours to work in the yard, I would get things done.
As soon as I can figure out my camera and posting pictures I will. Luck to all, and to all mothers I hope you have had a happy Mothers Day.