Help! Seedlings Dying
I'm hoping someone can help me. I started growing veg about 4 years ago and have been pretty successful for a novice. I have grown loads of tomatoes (no greenhouse, just in pots), runner beans, corgettes, carrots (though tiny!), chillis, brussel sprouts, chard, etc. Our old house had a big garden and a conservatory, I used to grow the seedlings in the conservatory and then move them out to the garden when ready.
Beginning of last year we moved into a smaller house with no room indoors to germinate seeds, but I was still determined to continue growing veg, again successfully using a seed tray outdoors and in big pots and trays after.
This year I can't seem to grow a thing. Not even my usually successful moneymaker tomatoes. The weather is better (dryer) this year than last. Only about half the seeds I plant germinate, and the ones I do get about an inch high and then keel over and die. Thinking it wasn't warm enough I built a 3 frame "mini greenhouse". Didn't make any difference. I then though thought that perhaps they were getting too hot in the "mini greenhouse" in the seed tray with the plastic cover on top. I removed the plastic cover, now nearly nothing germinates.
The only other thing I can think of is I have bought no new potting compost this year as I had half a bag left over from last year, but I have about 10 pots so spread this about. I can't remember if I used the bag compost in the seed trays or robbed it from other pots.
A long post I know, so sorry about that. So is the likely cause the compost, trying to germinate outdoors or overheating in my "mini greenhouse"?