On Starting Seeds and Greenhouses

Another couple of rainy, windy, cold days here in Iowa, so I'm inside again, starting a few last seeds and thinking about the process and how I might improve it. The seedlings in the picture above are the petunias I experimented with growing from seed this winter.

I was feeling spendthrift and lazy just going to the nursery and buying flats of petunias and other annuals already started, so I decided to try starting some petunias from seed in mid-March to see how it went.

I have started seeds before and it's usually worked fairly well -- the vegetable seeds I've started for my husband have been quite easy, and I've also started biennials like wallflowers and perennials like the 150 dianthus that edge my four L-shaped pond garden beds (although those are started in late spring and potted up outside until they are planted out in late summer, so they are different than starting seeds indoors under lights in winter and spring).

I bought a soil blocker this spring and used it for the first time with these petunias, and it worked quite nicely. As you can see in the photo, the petunia plants are coming along fairly well, although I had problems with uneven germination and size of plants.

Petunias are not the easiest plants to start from seed and grow inside -- first, they require at least two months of growing in warm, bright conditions, during which many things can go wrong: damping off (I run a small fan nearby to keep the air moving gently), drying out if you forget to water them or go away for a few days, and probably numerous other maladies that can afflict them. And the seeds are quite tiny, so Burpee's (the ones I found locally, so I didn't have to pay for shipping) are pelletized for easier handling, which is fine with me, but that makes them more expensive, and only half of the 50 seeds (2 packets) that I bought germinated, which is disappointing.

I also have some sweet peas and dahlias started from seeds on the top shelf, as well as some freesias just coming up in the pot below. The lights plug into a timer on the wall, and a small fan is on the floor nearby.

To grow them in my basement, I use florescent lights and a heat mat under the flat, both of which cost money to operate (even independently of their purchase cost). I calculated that the 24 petunia plants that I have managed to grow to this point have cost me more than three times as much, per plant, as buying them already in flower from the the least expensive nursery near me:

Cost of 24 Petunia Plants:

$ 3.00    50 Seeds (2 packets @ $1.50 each, only 24 of which germinated)
$ 2.00    Seed Starting Soil
$ 6.50    Cost of running two 32W light bulbs for 14 hours/day for two months
$ 2.50    Cost of running heat mat for two months
$ 3.00    Cost of running small fan (for all seeds)
$17.00

At the Amish nursery near me, a six-pack of petunias costs only $1.29, so 24 petunia plants costs $5.16, less than a third as much as it cost to raise them myself. Even if all 50 seeds had germinated, it still would have cost $17 for 50 plants, compared to $10.75 for 50 purchased plants, which would still be nearly twice as much. Hmmm!

Now, I know that not all plants take as long to start as petunias, and that there are other reasons to start plants from seeds besides saving money: only a limited selection of plants are available as starts locally, so if I want special varieties, I will have to grow them myself. Also, I'm serious about my hobby of gardening, and there's the argument that I really can't consider myself to be any sort of knowledgeable gardener if I don't know how to successfully propagate plants.

So I still want to be able to grow things from seeds, but I might have to re-evaluate how I do it. Much of the cost in my calculation comes from the long periods of running lights, which I would not have to do if I had a small greenhouse.

A Greenhouse?

Now, greenhouses are very common among British gardeners, who can hardly imagine gardening without one. But they're fairly uncommon here in the US, for several reasons: first, it gets MUCH colder here, so it costs a lot more more to heat a greenhouse in winter. (In England, many places hardly get below 20°F, compared to below 0°F here.) Also, it doesn't get as warm there -- in England, many gardeners grow tomatoes in greenhouses, because they just don't get enough heat to grow them outside. Here, a greenhouse is practically unusable in the hotter months (unless it is to sterilize soil).

Many British gardeners can hardly imagine gardening without one of these. (Hartley Botanic)

But this is more like what I'm eyeing: a 4'x8' lean-to style greenhouse.
(EarthCare Greenhouses)

I've been considering getting a small, relatively inexpensive greenhouse for several years now, but I wasn't sure where I would put it, until a few months ago a place occurred to me: The south side of my garage.

I had tried planting sunflowers and iris there to make it look less ugly, but I have realized that I should just consider it a "utility area" and use it as such. I removed most of the plants last week and will at least put a cold frame or two in this spot.

This area on the south side of my garage will never be pretty, with the gas tank, vinyl siding and tiny, ugly window. But it does get full sun and is relatively protected from wind, as well as being near electrical outlets inside the garage.

The eight-foot-long greenhouse would be just to the left of the gas tank, and the garage window could be replaced with a small insulated door, as the inside framing is already appropriate for that. Opening the garage greenhouse door on cold days would release less heat from inside the greenhouse than an exterior greenhouse door would.

I would probably only use the greenhouse in late fall, to protect tomatoes and herbs from frost, and in early spring, to start seeds. I could run a small portable heater on a thermostat in spring to keep the temperature above 50° or so. There would be a cost of heating the greenhouse (I have calculated using an online greenhouse heating calculator that during the months of March and April it would cost about $25/month to keep it at 50°), but the cost could be averaged over a number of flats being started at one time. Perhaps I wouldn't be able to start warm-season flowers and annuals in there until mid-spring, but cool-season annuals and vegetables would probably do well in there earlier in the year.

Of course, I can buy a hundred flats of petunias for the cost of a greenhouse, even the the inexpensive one I'm considering. Realistically, I will probably never justify the nearly $1,000 it will cost me to set up the greenhouse. But on the other hand, it might be fun to have one, and it might make me a more knowledgeable and experienced gardener (or it might just be a place to sit out of the wind on sunny, cold days, or just end up as a place to store pots, like so many gardeners' greenhouses end up...).

I'd like to ask readers, particularly ones gardening in cold climates, whether you have ever used a greenhouse successfully, and for any tips or recommendations on doing so (or not doing so, if you recommend against it).

Thanks for reading, and I hope your own seed-starting efforts are going well this spring! -Beth