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Growing Geraniums from Seed - 2009
...a continuing feature...

Sometimes things just don't go right. This feature story is an example of some of the things that can go wrong when starting geraniums from seed. I've left it up, but also have started a new feature on Growing Geraniums from Seed (2010) where things are going much more smoothly!

If you have the right conditions, growing seed geraniums (geraniums from seed) is relatively easy. Seed geraniums have the advantage of not carrying disease forward as propagating from leaf cuttings can do. And with seed geraniums, you're not limited to just propagating varieties you have, but have the full spectrum of seed geraniums that are available from seed catalogs.

World's Top 6 MixIn the past, most of my geranium seed has come from Stokes Seeds in New York. Their seed has proved to have excellent germination rates (around 90% for me), but can be a tad expensive. This year I decided to try a mix from Thompson & Morgan (US) and a single variety from Twilley Seed. Thompson & Morgan offers a World's Top 6 Mix of 5 seeds each of 6 different varieties for $11.95. Their no minimum $10 off offer (listed in their print catalog only) didn't hurt, either. The mix includes Geronimo (red), Hollywood Star (red with white throats), Picasso (red), White Orbit, Horizon Salmon, and Tango Orange. I also bought a packet (10 seeds) of Maverick Red from Twilley for $1.90.

Important note: See below for an advisory about hard seed, germination rates, and geranium seed vendors.

December 1, 2008

With the first snow of the season upon us, I decided it was a good time to get started with this project. My Stokes Seeds catalog recommends starting seed by December 20 for blooming plants (in 4" pots) by May 10.


Ready to goI usually start my seed geraniums on moistened white paper towels. The process is similar to doing a seed germination test. I also decided to try something I'd seen online, using a coffee filter instead of a paper towel. The coffee filter is a less porous paper which may reduce the sprouts and roots from penetrating it (one of the drawbacks of this method).

I moisten one side of a paper towel section and space the seeds on it. Since we have soft water at our house, I use cold water (bypasses the water softener) heated a bit in our teapot to moisten the paper towel. I'm not sure the salt in soft water could hurt the seeds, but I also don't want to take the chance.

Geranium seeds space on paper towel

You'll notice that some varieties of geranium seed are white, while others are dark.

Seeds on coffee filter

Although the assortment from Thompson & Morgan was supposed to have 5 seeds of each variety, the packets varied in number from a minimum of 6 to one packet that contained 15 seeds. The extra seed(s) is often included to make sure your results match any germination test percents marked on the seed packet.

BaggedWhatever paper you use, fold it over (note I kept the seeds to one half of each sheet of the damp paper) and place the paper towel or coffee filter containing the seeds in a labeled plastic bag.

four packSince I had lots of seed (from the packet that had 15 seeds), I also grabbed an old, clean four pack, filled it with sterilized potting mix, and placed a geranium seed in each cell. I covered each seed with a bit of peat moss and then top watered with very warm water. Sphagnum peat moss won't absorb cold water but readily absorbs warm water.

If most of these seeds germinate, I'm going to end up with more geraniums than I really want. I went ahead and used all of the seed, but do be aware that you can freeze geranium seed for a year or so and not lose much viability. I still have one packet of 20 ivy type geranium seeds on order. When it comes in, I'll start just a few of the seeds (5-6) and put the rest in the freezer until next year.

The four pack and all the bagged geranium seed then went downstairs to my plant room. My heating mat is under my plant lights, so I wrapped the plastic bags in a opaque trash bag before putting them on the mat. The four pack went into a half size plant tray with a clear dome to retain the moisture. Since I'd covered the seed in it with peat moss, I didn't have to do anything to block the light.

On heat pad

You want to maintain a temperature of 72-76o F for the seed, so a heating mat of some type may well be necessary. My heating mat came from Park Seed a few years ago and is still available there. They also have a cheaper mat without the metal frame that comes in several sizes. The best geranium germinating area I ever used was in a rental house that had a closet with a heat duct through it and shelves. It kept my geranium seed warm and dark.


Electric Grow Mat

Start your seedlings the most efficient, effective way possible with this innovative Electric Grow Mat! The ingenious design allows better airflow because the chrome wire cage ensures that the heat not only rises, it circulates! Just set your seedling flats on top of the Grow Mat and wait for those green shoots!

The heating mat contains wires molded into thick, protective black rubber for safe, long-lasting, durable use. The entire mat is surrounded by a chrome wire cage, which is also great for preventing children's inquisitive fingers from touching the heat! Just plug the mat into a 110-120 volt household current outlet (the ordinary 2-prong kind -- no more squeezing behind the refrigerator or descending into the basement to locate a 3-prong outlet!), place your seedling trays atop the chrome wire cage, and you're ready to grow! The mat measures 23 by 15 by 2 inches.


Waterproof Seedling Heat Mat

If you like to begin your garden indoors in late winter, low temperatures can sometimes make germinating seeds difficult and slow. You COULD keep the heat cranked up, of course, but why not just raise the soil temperature in your seed flats and begin the garden of your dreams right in the basement or on the kitchen counter? Let the Waterproof Seedling Heat Mat do the work for you!

This waterproof mat fits neatly beneath 1 standard-size seed flat or Bio Dome, raising the temperature of the soil to about 85 to 90 degrees F. You can't get much use from it in a zero-degree room, but if you've got a chilly basement or mudroom just perfect for starting seeds, plug in this mat and off you go!

There is no need to use a thermostat with this mat, though if you want to measure the exact soil temperature (for those hard-to-start seeds!), we've got a nifty little thermostat to do the trick. And the mat includes helpful hints printed right on, so you never need root around for gardening books when facing a new seed-starting challenge!

This is the smallest size of seedling heat mats, measuring 9 by 19 1/2 inches. If you want a larger size, consider the 2-flat size (20 by 20 inches) or the jumbo 4-flat size (48 by 20 inches).

Germination may begin in just 4-5 days or string out as long as 21 days, according to various seed catalog cultural information. To be safe, definitely start checking your seed by the fifth day. I'll probably check mine tomorrow, also, to see if I got enough moisture on the paper towels.

You definitely don't want your expensive seed to dry out or for the roots to grow into your paper towel. If the roots do penetrate your paper towel, you'll have to tear it and transplant some of it with the new seedlings.

There's a good video tutorial on germinating seed on paper towels on YouTube: Germinating seeds in paper towels. I really thought I'd learned the trick of germinating my geranium seed on paper towels from Crockett's Victory Garden (1977), but couldn't find it in any of my books by Crockett. When I did an online search, I found that lots of folks use this method.

December 4, 2008 - Reason Sets In

As I checked the moisture levels on the seed geraniums yesterday, I began to calculate the space I'll need under plant lights if I do get 80% or better germination. In one of those "What could I have been thinking" moments, I realized that the pack of 30 seeds, which turned out to have more than 45 seeds, the other packet of ten seeds, and another packet of 20 (still on order of which I'll plant only 5-6 and freeze the rest) will overwhelm my relatively small capacity under four fluorescent shop lights!

A couple of the packages of seeds seemed not as wet as I'd like them, so I added about half a teaspoon of water to each.

December 6, 2008

Geranium seedsThe Stokes Seeds order came in yesterday, so I got busy this morning and planted six of the Summer Showers ivy-leaf type geranium seeds that came in the order. I'd forgotten earlier to give you a good look at the size of geranium seeds. At right you can see that while small, the seeds are of enough size that you can carefully place them on the wet paper towels for germination with your fingers (instead of using tweezers).

Starting geraniums from seed

I've not grown the ivy-leaf type of geranium before, but this variety is supposed to be a "true cascading, base branching" type that should be ideal for hanging baskets for our back porch next summer.

I also checked my previous planting of seed geraniums, but saw no action other than the seeds swelling just a bit and showing the beginnings of a sprout getting ready to emerge. In a few more days (9-10 from seeding), many of the sprouts should have emerged and be ready to be moved to pots of sterilized potting soil.

December 20, 2008 Oh, no!

I've had a sinking feeling every time I've checked the geranium seed lately. Just one seed has germinated! If I weren't using seed from three different sources, I'd say I got some bad seed. But with three suppliers, it has to be my culture or practices.

While I haven't thrown any of the seed out, I have started some more seed (Summer Showers variety that I'd stored in the freezer). My guess is that I let the seed dry out. The sandwich bags don't hold the moisture as well as the freezer bags do. But I did have two or three bunches of seeds in freezer bags that didn't germinate either.

Any economy in this project is now out the window. I just sent a panic order to Stokes Seeds for a couple more packets of seed.

January 31, 2009

Happy GeraniumsWell, considerably humbled now by the near total failure of my seed to germinate using the paper towel and baggie method, I did get some starts from the traditional potting soil approach. I really racked my brain going through what could have gone wrong (bad seed, light getting to it, too dry, too wet, too hot, too cold, contaminant in the water...on and on). But my guess is that I didn't keep the seed in the dark. A close runner-up would be moisture control.

I moved plants out of fourpack cells where there was more than one plant today. I also changed my potting mix to include less lime and am now adding a bit of bone meal (can't hurt).

February 21, 2009

Geraniums in fourpackToday was transplanting day, as the biggest of the geraniums were outgrowing their fourpack cells. I use a variety of old flower pots and saved commercial containers for the transplanting.

Ready to repotI used a soil mix of half and half commercial potting mix and peat moss, with a liberal dose of perlite and a touch of lime and bonemeal.

When I extract the plants from the fourpack, I do break off the potting soil at the bottom (and the sides, if necessary) until the roots just barely show. Then I center them in the pot, being careful to both not break the stem, but to also firm the soil around the plant.


Since I use so much peat moss in my soil mix, I do have to heat some water on the stove so that the peat will pick up the water from a rather heavy bottom watering. I put about two inches of water in the bottom of the seed tray. Note that it's actually a doubled tray, the top one with holes and the bottom without holes. Using two trays aids drainage, but more importantly adds some strength to the trays.

The geraniums will stay in these pots until they are transplanted into the garden, flower beds, and planters.

March 30, 2009

Our geraniums moved outside under the cold frame last week. The came inside last night, as we had an overnight low of around 28 o F and some frost. They're pictured below on their way back out to the cold frame this morning.

Geraniums from seed

February 26, 2013

After nearly driving myself nuts trying to figure out what I was doing wrong with our seed geraniums this year, and as you can see above, I do commit some real blunders, I discovered that the seed we'd purchased from trusted seed vendors Stokes and Twilley Seed was either hard seed or simply bad. Hard seed as defined by The Free Dictionary is:

a seed that does not swell or germinate within its established period of viability. A hard seed has a tough impermeable coat, or testa, that does not allow water or air to reach the embryo.

Hard seeds are encountered most often in seed lots of leguminous herbs (clover, alfalfa, sweet clover), small-seeded vetch, and lupine. Their quantity depends on the conditions that existed during their formation and maturation. For example, in years of drought up to 60–65 percent of the seeds produced by red clover and alfalfa are hard. The number of hard seeds decreases after storage, which varies in time for different crops from several weeks to several years. The sowing of hard seeds results in non-uniform germination and sparse plantings. The impervious seed coats may be scarified before sowing to facilitate germination.

And as I wrote in a blistering rant on my Senior Gardening blog, "Any hard seed without an appropriate warning from the vendor is, in my opinion, bad seed." It's also a giant breach of trust.

At this point, I really can no longer recommend one seed vendor over another for geranium seed based on my current experiences. I do recommend doing a small germination test if you have enough seed. If not, I'd go ahead and scarify any geranium seed before planting to achieve a somewhat decent germination rate. It's not terribly difficult, and The Brown Thumb has a good page of instructions on Seed Scarification, Seed Stratification & Seed Soaking.

I finally compiled our various blogs on growing geraniums from seed into one how-to, Growing Geraniums from Seed.

From the at Senior Gardening


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last updated 3/22/2015