Tuesday, February 3, 2009

Propagating Petunias

I love propagating plants. Few things give me a shot in the arm like making 50 plants out of one. Young plants grow more vigorously than old ones. Propagation keeps your plants young.

Today I was pruning and grooming in the greenhouse. There's a chance spring will come. I am seeing new growth on the petunias. Petunias in February? Well, you see I discovered a few years ago that you can propagate petunias from cuttings. The trick is to get healthy new growth on the old plants.
In winter keep the soil on the dry side. Petunias can be extremely dry when the air is humid and cool.
Cut the old tops and all branches back to around an inch long.
When the new growth is two or more inches long, it's time to do cuttings.

prepare plug trays with sterile medium. I use a grower plug mix about 1/2 peat, 1/4 perlite and 1/4 vermiculite.
Take cuttings 2-4 inches long. You need to have at least one leaf node below soil.
Remove the lower leaves and pinch out the growth tip. Leave no more than 2 square inches of leaf on the cutting.

(since my petunias aren't quite to cutting stage , I will demonstrate the process with the following series of photos of sticking cuttings of scented Geraniums.)

Dip the cut end in IBA, or Root tone. Use a dibble, a pencil or sharpened dowel will do to make a hole so you don't wipe the powder off the tip as you insert into the medium.

I set the tray in a pan with water treated with banrot to reduce the incidence of stem rot (no roots to rot, yet)

Water the soil thoroughly, and cover with a dome lid to retain humidity. Drain and set in a tray with no holes to protect the shelf under the lights.

Place over heat under lights. Temperature should be maintained at about 70 degrees, no cooler than 65 F.
Within 30 days there should be roots.

Check often so you can remove any problems like leaves that are rotting or molding before any spores spread to the whole flat. As soon as they're rooted remove the dome. Do not expose to very warm dry air, as they will wilt easily until hardened a bit. Pot them up and grow on until you can put them in larger containers for the summer season. Keep these young plants for the next season.
Hmm now if I could just grow me a new young body.


  1. Thanks for posting the how to for rooting cuttings. I had been looking for just such a posting.

  2. Hi! Can you propagate petunias even without rooting powder? I'm having all sorts of problems doing that.

  3. Thank you for posting this, i love petunias and living in africa with the sun they look immaculate when they are flowering.

  4. If you're still wondering if you can propagate with out rooting powder, yes you can, but the biggest problem you will have is fungal rot. Spores are present everywhere and so everything needs to be clean.
    IBA, speeds up rooting, as it is a hormone.
    Sometimes I have more success than others. I blame it on the moon when things go bad. If you dip the whole cutting in a Chlorine bleach solution, 1 T. per gal, You can kill alot of problems. After 10 minutes in the solution rinse the cutting well, and pat dry with paper towel, then stick in the medium.
    good luck.

  5. Can you please tell which season is right for planting the cuttings of petunias ?