One of the Joys of Maturity
Growing Geraniums from Seed
If you have the right conditions, growing seed geraniums (geraniums from seed) is relatively easy. I set out in 2009 and again in 2010 to describe the process for others. I ended up experiencing almost every failure one could, along with making some really stupid mistakes along the way. Those blogs remain online as an exercise in writer honesty and humility. And since writing those pieces, I've gotten my act together again, as we've successfully grown seed geraniums for over thirty years.
Growing geraniums from seed has the advantage of not carrying disease forward as propagating from leaf and stem cuttings can do. With seed geraniums, you're not limited to just propagating varieties you have, but have the incredible variety of seed geraniums that are available from various seed catalogs. Self grown geraniums can be timed to match ones own transplanting schedule in the garden and flower beds.
And...you may save a few bucks growing your own geraniums from seed over purchasing plants at a garden center or discount store if you avoid the mistakes I made in 2009 and 2010.
We now get most of our geranium seed from Twilley Seeds. They carry our favorite Maverick Red variety (shown above right) and many other varieties of geraniums. We also got some good ivy leaf geranium seed in 2015 from Burpee. Stokes Seeds, another reliable seed vendor, carries a full line of good geranium seed. Shopping for bargains on geranium seed never seems to work out for us. Inexpensive seed often turns out to be old seed that doesn't meet our expectations for germination rates.
We've found that germinating our geranium seed on brown (unbleached) coffee filters or unbleached white paper towels works best for us. I prefer the coffee filters over paper towels, as the emerging roots don't stick or grow into the coffee filters as much as they do with paper towels.
The seed is spaced on a damp coffee filter which gets folded over the seed to ensure the seed gets all the moisture it needs. The coffee filter then goes into a Ziplock freezer bag (sandwich bags tend to let out too much moisture) with just a bit more water added to the bag.
I germinated our geraniums for years in total darkness until a reader clued me into a seed producer's fact sheet that suggested one would get better germination with a bit of light on the seed. (My thanks to Mike Bryce for that info.) So instead of hunting for a warm, dark closet to germinate our seed, it now goes into a covered plant tray under our plant lights. The tray rests on a soil heating mat that is thermostatically controlled. Anywhere in the low 70s (70-75° F) should give good results.
In just a few days, often less than five, the seeds begin to sprout. Before the sprouts get too big, I very gently lift them from the coffee filter and place the seed in a slight depression in some sterile potting mix in a 3" pot or a fourpack cell. I then lightly cover, or more accurately, surround the seed with vermiculite to hold in moisture.
Note that one can also start geranium seed in pots or insert cells on sterile potting mix, pressing the seed into the damp mix, lightly covering it with soil or vermiculite. When we've done it that way, the pots or inserts still go into a tray covered with a clear humidome under our plant lights and over a soil heating mat. With the coffee filter method, even though each seed has germinated, not every one will flourish and produce a plant. But moving the seed to individual small pots saves having a few cells in fourpack inserts without plants. Using individual 3" pots allows me to spread out the plants as they begin to put on some size.
We ended up getting nineteen good seed geraniums in 2015 from twenty-five seeds started from seed purchased in early 2014. That comes out to about a 76% rate of germination and survival. In 2016, we only had a 63% germination and survival rate, a low figure that reflects using seed about a year older than I'd normally use. For 2017, we're using all freshly purchased seed. Of course, seed houses buy seed in quantity and store it in temperature and humidity controlled conditions, sometimes selling the seed over several years.
As soon as the seed pushes out of the vermiculite and is an upright, if tiny, plant, I move them off the soil heating mat. While geraniums may need temperatures in the 70s to sprout, once up, they like a bit cooler temperatures.
The plants stay under our plant lights, which are simply 48" shop lights with 5400-6500° K fluorescent tubes in them. I keep the lights several inches above the top of the tallest plant. If the leaves begin to bleach out, I know my lights are too close to the plants. But from this point on, geraniums are pretty forgiving plants.
In about a month, one should have some very healthy looking, small geraniums plants. The images left and right taken on February 27, are of our 2015 seed geraniums. The mixed Orbit series and Maverick Reds seeded on January 19 are on the left, and our Summer Showers ivy leaf (trailing) geraniums started on January 29 are on the right.
Other than regular, usually weekly, watering, the geraniums don't require any special care. The potting mix has all the nutrition they need at this point, so fertilizing isn't necessary or recommended. I only bottom water our plants, as they're grown in watertight trays that makes bottom watering easy.
We often experience a real logjam under our plant lights each spring, necessitating a bit of inventiveness to keep all of our plants and transplants growing well. We're fortunate that our large, old farmhouse has a sunroom with lots of south facing windows. Unfortunately, the builder didn't duct the room into the heating and air conditioning system, so the room is hot in the summer and cold in the winter. But with an oil heater, I can usually begin moving geraniums, onion and brassica transplants, and even some gloxinias to the room in late January or early February.
While the baby geranium plants in the three inch pots initially used are really cute, they rather quickly need more root space. Just two months after seeding the plants, they get moved to 4 and/or 4 1/2 flower pots to continue their growth. At this point, sterile soil isn't necessary to prevent damping off disease, as the plants have developed pretty tough stems. I use commercial potting soil cut with about one-third peat moss for the transplanting. Although I avoid potting soil with fertilizer pellets and perlite in it for seed starting, it's ideal for plants at this stage of growth.
I did this transplanting, as I often do, outside on a warm spring day. Our nights, however, weren't warm enough yet to risk moving the plants under our cold frame to begin hardening off. So once again I had to get a little creative on plant space, putting both our standard geraniums and the ivy leaf ones, now in hanging basket pots, on our dining room table in front of a large, east facing bay window.
Plants grown inside under artificial lighting or in a greenhouse need to be hardened off before being transplanted into the garden. Indoors, they've not had to face the rigors of bright, hot sunlight, cool nights, UV radiation, and strong winds. If not hardened off, transplants often quickly fail under the harsher outdoor growing conditions.
We harden off our transplants under a homemade cold frame. The frame gets completely closed at night to hold in the warmth of the day, but is opened gradually through days to allow our transplants more and more exposure to the harsher growing conditions outdoors. During this time, stems and leaves toughen, getting the plants ready to survive in the ground.
Those lacking a cold frame could easily employ a sheltered area on a porch, gradually moving the plants each day into more and more sunlight. We like the cold frame, as it allows us to get an early start, being able to put plants under it even while we still experience overnight frosts and light freezes. (Note, we've also had times when everything had to come inside for a night or two of freak, late, hard freezes (20° F stuff.)
Our old, wooden cold frame rotted out last year, so I constructed a new one that wouldn't rot out, made of PVC pipe and fittings. I'm not entirely happy with the new frame, as I made it too tall, allowing it to dissipate too much heat on cold nights. It's also too light, having blown away in the wind a couple of times. But I have all the parts necessary on hand to build another to more moderate dimensions, weighted with a bit of concrete to add ballast. Together, the two frames are sized to fit into and over one of our long, narrow (3' x 15' interior dimensions) raised beds to extend our growing season well into the fall.
Typically, our geraniums are some of the last of our transplants to go under the cold frame to harden off. The process of exposing them to outdoor growing conditions takes a week or two.
What do we do with our geraniums?
We grow lots and lots of geraniums each year, sometimes forty or more! We do so because we like to put a geranium at each corner of our raised garden beds. We also use them at the ends of rows, replacing the wooden stakes used in planting with something much more attractive.
Geraniums mixed with petunias, vincas, marigolds, and snapdragons almost steal the show from our vegetables, the reason we garden. And while vegetable crops come and go in succession through a growing season, our geraniums and other flowers stay put, gloriously blooming all summer and fall.
If you came to this page looking for my previous comedy of errors geranium blogs, they're still available as the first two links below.
We had successfully grown geraniums from seed for years. Then in 2009 and again in 2010, I decided to record the process in blogs. Whether I got too cocky about our previous success or just had bad luck, I don't know. I made some horrible mistakes those two years, and then and later suffered from getting bad seed.
After being thoroughly humbled about my geranium growing abilities, I became much more careful about our practices, and we returned to growing all the geraniums we could use and give away once again. It's a good feeling.
We're now growing less geraniums than in the past. Having used them at the corners of our raised beds for years, I think we've run into some rotation needs, as our 2016 geraniums were pretty, but not spectacular. Even though I'd dug out the soil from the corners of the beds and replaced it, I think the ground needs a couple of years without geraniums. Instead, I plan to use vincas at the corners of our raised beds in 2017, spacing our geraniums along the sides of the beds.
Even with some new physical challenges from hip and heart surgeries in 2015, gardening proves to be one of my greater joys in life. I hope the Lord allows me to keep doing it and blogging about it for some time to come.
Contact Steve Wood, the at Senior Gardening
last updated 1/8/2017