How to Grow Geraniums from Seed. Easy, step by step instructions on how to grow zonal geraniums from seed. For earlier flowering plants starting in February is recommended but this can be done later too.
Are Geraniums Hard to Grow from Seed?
No but you do need patience. But they are slow growing so starting earlier in the season is best if you wish to have flowers this summer. Otherwise you can start them later then overwinter them for the following summer. It can take between 13 and 16 weeks to get blooms.
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Why Grow Geraniums from Seeds
You may want to grow geraniums from seeds if there is a particular variety or color you cannot find in your local garden center. Or if you just love growing things from seed for your garden, like I do.
Otherwise you can just find plants very inexpensively at big box stores, nurseries and grocery stores.
How to Plant Geraniums Seeds
As with any seed starting make sure your containers are clean and sterilized. You can can start seeds in any container with good drainage and potting soil. Personally, I prefer flats or larger containers as opposed to individual 6 pack or cells.
This saves space on my seed starting rack. But I have also re-used the 6 pack containers.
To avoid problems with damping off (a fungus) a sterile mix is often recommended. In the video I tell you how to can sterilize regular potting soil if you don’t want to buy expensive seed starting mix. See this post for my comparison of Seed Starting mix vs Potting soil
Fill the container with 2 to 3 inches of your potting mix. Sow your seeds in the cells or an inch or so apart in your container. I usually have the soil about 2 inches deep.
You will be potting these up into larger containers later on so deep soil is not necessary.
Geraniums Need Light to Germinate
Lightly sprinkle the tiniest amount of potting mix on top or use a bit of vermiculite. Press into the soil to make sure there is good contact with the seed. Geraniums seeds need light to germinate.
In the photo below I used chick grit as it claimed to help with fungus but I have not been able to find this without additives now. But if you can find it without any nutrients added then it is a good option to vermiculite.
Set the container into a tub or tray of tepid water and let the soil soak it up. You can also spray the top with water to help moisten it. Bottom watering makes sure you don’t dislodge the seeds.
Cover the container with plastic wrap, a dome (to the right in photo) or something to help retain moisture in your container.
With the large salad containers I often use, the lid works wonderfully. You can see what I mean in the video.
Geranium seeds need Warmth
Place the trays or containers in a warm place with bright indirect light. Temperatures should be around 70 degrees or higher during the day and not get below the 60’s at night.
Since starting early is highly recommended using a heat mat and lights are helpful. See my inexpensive set up here: Indoor Seed Starting for a Beautiful Garden
Don’t have a seed starting rack or heat mat, my friend places hers on top of the refrigerator. Watch for germination which can range between 3 to 4 weeks. I have found a heat mat really speeds this up, I have this one.
You can grow them in a sunny south facing window but grow lights are best. Leave the lights on for 12 to 14 hours.
Geranium Sprouts or Seedlings
Geraniums sprouts or seedlings look like baby geraniums. Go figure.
In the photo above you see some of the cells were crowded with seedlings. I had sowed extra seeds as they were old and I did not expect good germination. I was wrong.
Fertilize once a week with a very diluted liquid fertilizer that is diluted to a quarter strength. If you potting soil is amended with fertilizer skip this for awhile.
Once they get 3 sets of leaves pot up into 3 or 4 inch pots. Some claim that transplanting stunts growth and prefer cutting off the extra seedlings.
Geranium seeds are quite expensive and that is a total waste to just cut them when pricking them out and planting up is so simple. I share how to easily transplant them in this article: Thin Seedlings WITHOUT Cutting Them.
Once you have transplanted the seedlings into larger pots it is claimed that you can start feeding them full strength but I had a batch get burned from this so I recommend a weak solution for a longer period of time. Or use a liquid worm casting tea, I have never had issues with it burning.
How to Collect Geranium Seeds
But collecting seeds from your own plants is easy too. Here is what a geranium seed pod looks like.
Note the dried up bloom. To keep your geraniums blooming, deadheading is essential but if you want to collect seeds from your plant then let the blooms dry up naturally on the plant. They form these spikes that contain the seeds.
When the seed pod opens it will look like this.
One pod will contain many seeds. Collect the seeds at this point and store in a dry, cool place. I use an paper envelope or put in a small jar (no lid) until I will sow them.
Harden Off Geraniums
When frost free weather arrives it is time to get your plants ready for planting outdoors. Zonal geraniums are a tender perennial and cannot survive cold temperatures.
Prepping your precious plants for the outdoors is essential as inside they have been pampered. Outdoor conditions are more challenging and the plants need to toughen up.
Give it a good week. Place the geranium plants outside in a protected spot. Out of the wind and partly shaded. Morning sun is great if it isn’t too hot yet. Only leave them out for a few hours the first day, then gradually expose them more and more to the outside conditions including sun.
Over the course of the week they should toughen up enough (if you don’t have blazing hot temperatures yet) to live out in the garden.
Until next time….