New to gardening

Hi Armandii,
Thanks for the info on vent openers. I will start searching for one so that I am ready for next year.

 

If you grow seedlings that are "tender" or "half hardy" and are, in effect, using your greenhouse just to start them off early then it is important that they don't get "too cold".

A greenhouse will keep its contents snug, compared to them being out in the elements. It will keep both chilling and drying winds off them, and keep the heat in at night. Usually it will keep the night temperature a few degrees warmer than the outside temperature (but if we get really cold for several days on end you will find that the temperature will be the same inside as it is out - bitter!), and because ti will warm up during the day it has more heat "stored" so that at night the temperature inside doesn't fall as low as outside does.

Also, in the spring the nights get shorter, so when the temperature starts to fall outside (lets say around midnight) the fall inside the greenhouse starts a couple of hours later (so say 2am). By 6am the temperature outside starts to rise, so the greenhouse has only has 4 hours of falling temperatures. This means that the frosts we get in April / May will not [usually - unless we get "blinking cold" at that time of year!!] have any impact on plants inside the greenhouse.

However, some plants need a bit more than "frost free". For example, Tomatoes will survive at Frost Free temperatures, but they will "stall" if the temperature falls below 10C, and once they have stalled it takes them quite some time to get going again. That's the reason that people like to provide some heat in their greenhouse in the Spring.

So it depends what you grow, and how early you want to start. In the main your will probably get away with no additional heat. It would help if you can put some horticultural fleece over the plants [in the greenhouse] on chilly nights, and if your greenhouse is hear the house so that, in an emergency, you could carry the plants to the utility room or garage, then you could do that. You will probably only get that sort of cold Spring night 1-year-in-5, or maybe only 1-year-in-10 (and if you live in Cornwall 1-year-in-never!)

The best non-electric heater is a bottle-gas one. It has a pilot light and thermostat so will only come on when needed. It does generate some condensation though (which electric would not), and condensation encourages moulds. This is not usually a problem in Spring, but might be if you wanted to (in the future) use the heater in the middle of winter (to keep some more tender plants alive).

Least good is a Paraffin heater. These generate more condensation than Gas, the paraffin [fuel] costs a lot more, you have to light it on cold nights (so you have to judge if it will be cold, or not - and you have to be at home!), and there is no thermostat [unless you buy a very upmarket model] so it will burn from the time that you light it [i.e. even if the night starts off warm]. If the wick is not correctly adjusted you can come down in the morning to everything covered in soot!!

If you are going to heat the greenhouse then consider lining it with bubble-wrap. The money you spend on Insulation will be easily paid-back on what you save on fuel (just like insulating your house does)

Seed compost tends to be very fine ("sandy"). This stops the seeds getting waterlogged, and makes it really easy to prick them out - the soil falls away from the roots. It has no, or almost no, nutrients (again that is important for seeds).

It is better to prick out into something with more "body" - such as a multi-purpose compost. (However, I have found that the ingredients of multi-purpose has changed over the last few years, and getting the watering right, and "compaction" [which can cause water logging and thus the seedlings to struggle/die] has increased; I now mix 10% Perlite [by volume] with multi-purpose for pricking out seedlings into/growing on).

You shouldn't have to water the seed trays if they are in plastic bags - the water can't go anywhere, so any condensation will run down the bag and back into the seed tray. If the seeds don't germinate for weeks/months then some water will find a way to escape, so if they then get dry take the tray out of the bag, stand in an inch or two of water for 5-10 minutes, and put back in the bag.

As soon as the seeds have germinated. Open the end of the bag for a day or so (to get the seedlings used to the outside world!), then remove the bag after that. And move them to stronger light (if they were somewhere more shaded - under the greenhouse bench for example - they don't need strong sunlight to germinate, and indeed might get too hot in plastic bags sat in the sun, so they could be somewhere with no direct sun whilst germinating; mine are on windowsill propagators until they germinate, then they go into stronger sunlight). Again, no sudden changes, so acclimatise them to full-light over a few days (give then an hour or two, and then put back under the bench, for the first few days)

When they are big enough Prick them out into modules, or 3" pots, or similar. Mollycoddle them until they are decent-sized, but still small, plants and then plant the hanging baskets. If you can hang the baskets in you conservatory / greenhouse then you can do this at any time the plants are big enough, if not then you should not do it until the outside temperatures are warm enough - tender / half-hardy plants shouldn't go outside until danger of frosts has passed.

I see the names used as if they are interchangeable, but I don't think they are!!

I put a very thin layer of Vermiculite over seeds that I sow. It lets the light through (some seeds need a bit of light to germinate), and stops green-muck, algae etc., growing on the surface. It keeps the moisture in a bit as well.

I use Perlite to "open" compost so that roots can grow through it more easily. It also improves the drainage (you have to water more often, but you are less likely to over-water). You could use a small horticultural sharp-sand or sharp-grit instead. (But don't use any old / "builder's" sand)

 

Useful if you are not around to open the vents - shift working / away from home / ... forgetful?!!!

I don't use them because I like to open the vents away from the wind wider, and I like to have vents open at night (when the night is warm enough - but that temperature would be cold enough that automatic vents would be fully closed)

Get decent quality ones. The cheap ones may struggle to lift the weight of the vents and/or fail (and a roasting hot greenhouse will for sure kill the contents :( )

Some types require that you bring the "expanding wax cylinder" in the for the winter to prevent damage in the cold. Check if the ones you buy need that, and if so put the late-autumn date in your diary

 

Hi Kristen,
What amazingly comprehensive answers to all my questions.
Sorry I didn't see it earlier but we have had an amazingly busy day soaking up the sun with the grandchildren - the whole reason for making the garden look lovely.
If you don't mind I'm going to print out this topic and make sure I keep it in my gardening folder (lol yes I have a folder as I am so forgetful, so I keep notes on everything).