Growing Seedlings Without a Greenhouse

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Kale seedlings

Historically, a dowry is the booty a bride brings to a marriage, which might be money, fine linens, or a good milk cow. This tradition may take many forms. A few years ago, I entered a new relationship bringing along a cold frame and adjustable tabletop plant light. But in hindsight, Roger had me from the start. On my first visit to his house, it was hard to take my eyes off of his glowing three-tiered plant shelf, perfect for houseplants in winter and veggie seedlings in spring. It began to feel like a very good match.

If you don’t have a greenhouse, you know how important it is to have a dependable source of light for your seedlings. For 20 years my tabletop plant light served me well. Now it lives with friends who are just getting started as gardeners. Although these special fixtures (like Hydrofarm’s Jump Start models) are costly to buy at $70-$100 USD, they make growing seedlings so easy (and they last so long) that they are a good investment.

Onion seedlings
Onion seedlings in a growhouse where they are protected from the worst of cold weather.

You can get good light to seedlings cheaper with a florescent shop light, and it’s not difficult for resourceful people to rig up a way to adjust the height of the fixture with chains fastened to the ceiling. Ideally, you want the light to be less than 2 inches from the tops of plants, but some seedlings gain height faster than others. Raising the slower growers by placing them atop books or boxes is often the easiest way to get them closer to the light they crave. You should also change out tube bulbs every three years or so, because they lose some of their brightness with age.

It is not necessary to invest in the very intense lighting systems that hydroponic growers use, because vegetable and herb seedlings live indoors for but a few short weeks, and regular florescent lights are ample for their needs. Besides, once seedlings are up and growing, gradually exposing them to more sunlight is the best way to prepare them for life in the garden.

Growing under lights
Growing under lights

Halfway Housing for Seedlings

Many gardeners use cold frames to provide a semi-protected environment for seedlings, or you can use a growhouse, which are popular in the UK but have never really caught on in the US. Go figure! For the last couple of years I made a primitive growhouse by wrapping plastic around a metal shelf on my deck, and onion, cabbage and hardy herb seedlings loved it.

The problem with having plenty of cold frame or growhouse space is what happens when the weather turns so cold that all the plants must come into the house. With space under lights occupied by tomatoes and peppers, a cold snap may lead to flats of onions and cabbage cousins all over the house – on the floor, on the washing machine, and occasionally in the bathtub. Roger says he doesn’t mind, because we have this huge thing in common: we know where those seedlings are headed, and we’re both hooked on garden-fresh, organically grown food.

By Barbara Pleasant

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Show Comments


"Great advice - love the picture of seedlings growing everywhere around your home! I hope you don't mind but I've put a link to it on my Facebook Page - Greenside Up - a page to help beginners get growing."
Dee Sewell on Friday 5 February 2010
"A great article, Barbara! May I jot down a few things I do that I think will be helpful? It is possible to get Angle-Poise lamps with weighted bases (or clamps) that take small fluorescent bulbs. Also make sure that your bulb has a K rating or colour of Daylight or 2700K. Essentially this means the light looks slightly blue to human eyes but the plants 'see' a greater PAR (Photosynthetic Active Radiation) and so use far more of the light, making it more cost-effective for use. If you need to raise a small baby plant up, use an up-turned plant pot at least of the same size that the baby plant is in so the pots form a stable and waterproof 'X' shape. You can adjust height this way by using different pots as the seedlings mature. I usually raise ALL my pots at least 1" off the base level so the pot is never sitting in water, plus the run-off water evaporates upwards to the underneath of the leaves straight into the plants stomata, yum, yum!"
Kevin Hannan on Friday 5 February 2010
"ooops! Sorry! The K rating is 6400K! It came to me in a flash as I made my morning cuppa! Also, if you can, try to leave the light on for 18 hours a day (suitable for most seedlings) and if you are forgetful like me (!) put it on a timer switch!"
Kevin Hannan on Friday 5 February 2010
MARY on Tuesday 9 February 2010
"Mary - if your seedlings aren't thriving once they have germinated then it could be down to the potting soil/compost, the temperature, the amount of water or the light. All these need to be right for them to do well. For potting soil/compost, I would look for something of high quality specifically for seedlings (your local garden supplier should be able to help here). They shouldn't need feeding in the first few weeks if the potting soil/compost is good. They need to have enough space to grow and be moved into their own pots when the reach a few inches tall, as overcrowding can stunt growth too. See our Growing from Seed GrowGuide for more details."
Jeremy Dore on Saturday 13 February 2010
"I need help in creating my own cold frame. I want to build one from scratch. Any suggestions in how I get started?"
Carol on Tuesday 23 February 2010
"Hi Carol, for a simple solution just take a look at this article Barbara wrote: We hope to have a more specific article on how to build cold frames in the future."
Jeremy Dore on Tuesday 23 February 2010
"Hi I'm picking up on what Kevin had to say re a suitable light source - I have a sewing lamp with a 'daylight' bulb. Do you think this would do the trick? Francesca"
Francesca on Saturday 27 February 2010
"Hi Francesca, I think it would probably work for a small number of plants but you might find that it gives off too much heat. The special fluorescent tubes in these plant lights don't run too hot (mine only raise the temperature of the plants by about 5C / 10F) and they are very bright. So, you could check with a thermometer and then give it a try."
Jeremy Dore on Saturday 27 February 2010
"Hi Francesca, Jeremy; May I elaborate on Jeremy's answer? If your sewing bulb has a metal filament like the old style 60w/100w bulbs then absolutely not, no. Those will not work and the heat will be far too much. If it is a fluorescent tube/compact flour/t tube then, yes, for the most part they will work and will remain much cooler than a filament bulb. Please remember that for every double the distance between your light and plants you will reduce the light by 4 times. You can think of using foil or white plastic to create a reflector of sorts to keep as much light trained in and around your bulbs but do remember to allow a vent at the top for hotter air to escape and a vent at the bottom for fresh air to be drawn in. Jeremy says 'special flo/t tubes', they really are not special, you can get them at most supermarkets, don't pay over the odds because they are 'special'. For example an aquarium plant tube costs twicw/three times as much as the same (brand/kelvin/everything) light in the major store. You need a 2700K ('blue') for vegging and 6400K ('red') for flowering. Most generic lights are around 3500-4500K which is no good."
Kevin Hannan on Saturday 27 February 2010
"@Comment by: Kevin Hannan on Saturday, February 27, 2010 2700K is WARM (yellow orange) not blue. 6400K is for veg as it is daylight temp. "
Yardsnacker on Sunday 13 February 2011
"We pieced together a lighting system that cost far less than the grow lights. I found 2-bulb shop lights at Lowe's for $13 USD each, and have 3 per shelf. Total cost: $39 USD for the fixtures, which beat by far the $70 we would have had to pay for a 6-bulb fixture. So check around, see what you can jerry rig."
CB on Sunday 13 February 2011
"@yards = ooops! Sorry! I get it the wrong way round sometimes - I'll double check next time! That's the beauty of this place, everything gets checked many times over by other people! Thanks and sorry for misleading other readers. ;-)"
Kevin on Monday 14 February 2011
"I'll be visiting your site again to gather some more valuable information. - Greenhouses"
maynard638 on Thursday 26 July 2012
"Grow light comments are focused on vegetables. What about starting flowers and other perennials inside? What are the distinctions that require a different protocol?"
Joe on Saturday 11 February 2023

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