I'll be honest from the outset - this article is a ploy so I can tell you about the best seedling propagator available, the 'Vitopod' heated electric propagator. I'm giving you the other options and the reasons why indoor propagation works for me but I got so excited about the quality of this propagator I just had to write about it! (No, I don't get out much). Obviously this is the time of year to make your final decision on what you want to grow but also the best way to get them growing. In my opinion you are better off starting most crops off inside and planting out when conditions are more favourable.
It makes sense to start your plants off out of the elements but also with our short Summers it's worth getting a head start on the growing season. Plants started off in March or April will already be 6 weeks old when it's warm enough to try your first sowings outside so the your harvest date will be 4-6 weeks sooner accordingly.
There are plenty of reasons why I like starting indoors, here's just a few:
Slugs Emerging seedlings are at a high risk of being polished off by slugs or snails. A four week old healthy lettuce seedling can withstand a bit of nibbling but the tiny seed leaves on an new emerging plant are wiped out with one bite. Slugs can happily (and invisibly!) wipe out whole rows of baby plants leaving you wondering if they ever germinated at all.
Weather April can be an unpredictable month with warm days quickly changing to cold and nighttime frosts still being likely. Keeping cold wind and rain off new seedlings will make a huge difference to their growth with a bit of indoor pampering paying dividends in the long run.
Ideal Conditions As a rule of thumb the optimum germination temperature is around 18 -21 degrees for most crops and 24 for warm climate crops like tomatoes and courgettes. Clearly you have to start the warmer crops indoors but you'll also get a much better germination rate where conditions are spot on. Use a heat mat, soil warming cable or a heated propagator with a thermostat for perfect results.
Bottom Heat Seedlings germinating naturally are given the signal to start growing when the soil reaches the required temperature. Seeds will germinate quicker and produce a healthier seedling when treated to warm a compost bed and this is what we mean by bottom heat. Important: While warmth will help your seeds germinate more quickly it is important to remember to remove them from the heat once they have sprouted! Too much warmth after sprouting can cause your seedling plants to become leggy and weak.
Where to grow? You can start seeds off on a windowsill but the problem you will have is insufficient light. Seeds need moisture and heat to germinate but once the seedling starts to grow you will need plenty of light otherwise the plants become leggy. A windowsill is a reasonable option if you don't have any other choice however and placing a mirror or reflective foil behind the plant will help to bring light from more than one direction.
If you are lucky enough to have greenhouse or polytunnel then obviously this is where you'll be starting but you still need a source of heat at this time of year. You can use a heat mat, soil warming cable or electric propagator or if you want to be more traditional you can build a natural hot bed.
Heat Mat Heat mats are rolls of foil containing a soil warming cable. They are available with or without a thermostat but I would recommend thermostatic control for all electrical products as it keeps the optimum temperature as well as saving your electricity bill. Place the ssedling trays or pots directly on the mat.
Soil Warming Cable We use a 'Parsene' soil warming cables and thermostats in our tunnels and supply the 12m cable and thermostat on our website. To use the a soil warming cable correctly you need to construct a bench of moist sand which you bury the cable into. Here's the trick though: the sand needs to be kept damp to transmit the heat properly so it's best to line the beds with a plastic sheet to keep the moisture in. If you want to go one step further (we did and it works) you could use a 50mm foam insulation board for the base which helps keep the heat in.
"This is simply the best heated propagator on the market. Best Buy Propagator." BBC Gardeners' World magazine Look, from the outset this is an expensive propagator, there's no getting around that fact. It is however simply the best electric propagator you can get. It has a number of unique design features which I'll cover but what really impressed me is the quality of construction. It's easy to assemble with very high grade acrylic sides and lid which are bolted together and fit neatly into the fully enclosed heated base. As I write this I have it sitting on the office floor beside me and I literally can't wait till the weekend to try it in the tunnel.
Stackable The Vitopod comes in two sizes, a double and single unit. The acrylic sides are bolted together with high quality plastic nuts and bolts and are very easy to put together. You can buy extra height units meaning the propagator and be increased in height to accomadate taller plants like tomatoes, chillies and peppers. I have always found standard propagators to be lacking in this respect when a controlled environment is needed for longer with these warm climate crops. The Vitopod is unique in it's adjustable layers and can be built up to 4ft high if required. Each layer is 15cm tall and can be easily slotted to the tier below.
Very Precise control The Vitopod propagation unit uses a built in digital thermostat which can be accurately set in 1 degree increments between 5 and 30 degrees celcius. The thermostat has an easy to use digital display which is water and humidity proof.
The heated base is fully sealed and offers an even temperature across the surface with no hot or cold spots.
Large Ventilation Vents Large well made vents are provided for good air circulation for healthy plants and to prevent damping off.
Quality As I've already mentioned it's the quality of this unit that really stands out. I love well built products and was impressed from the moment I unwrapped the first piece.
This is a proper piece of equipment, maybe not for the beginner gardener because of the price but a very worthwhile investment if you're hooked and want to continue growing vegetables for a number of years. The best heated propagator we've seen, a serious piece of kit.
Small Vitopod - Fits 6 seed trays or 18 seed pots.
Large Vitopod - Fits 12 seed trays or 55 seed pots.