It's a good time for peppers. I just started mine. I'll be starting the tomatoes in anther three weeks. Squash is best directly sown outdoors when the weather is warm enough, or started indoors two to three weeks before that time (this depends heavily on what squash you're growing - some take a very long time to mature). I've never grown cabbage or brussels sprouts, but I believe in our climate, brussels sprouts should be started about 4-6 weeks before your last frost date and cabbage should be started about 4 weeks before. If you have a cold frame, they can be direct sown outdoors a couple of weeks early.

BP

Thanks BP. Guess I'll have to start my peppers soon. We have clay soil that we have been amending each year with compost and cover crops. It's improving but is still heavy and that's why I was wondering about starting things inside. Marg

This is approx. our 30th year vegetable gardening, mostly in the Ottawa area. For onions and leeks, start around Groundhog Day (Feb 2) under grow lights, very cool conditions. Basements ideal.
We start our peppers, eggplant, tomatoes about 7 weeks before we expect to plant out, so mid-April approximately. We start the seeds upstairs where it is warmer, then as soon as the young plants are growing well, we put the tomatoes in the basement under grow lights and leave the peppers and eggplants upstairs where they are warmer. Really recommend the use of 10-52-10 plant starter fertilizer every two weeks - makes a big difference - when we put our tomatoes outdoors, some of them already have flowers. Around first of May, we start (indoors) the pumpkin, butternut squash and canteloupe seeds. Everything else, we start directly outdoors.

Thanks for the info Shapiro. I haven't planted to much yet, just peppers. From what you say, I will start my maters soon and maybe wait another 2 weeks to start my Butternut and Spaghetti squash. When do you start your herbs, I was thinking of starting some of the basils since we like pesto with our pasta! Marg

Shapiro...thanks for that advice, really appreciate it! Marric, I started some herbs indoors under growlights already, the back of the seed pack usually tells you when to start feb/march/apr.

Shapiro, what i sthe purpose of the 10-52-10, as suppose to 10-10-10 fert? I already have a few kinds of NPKs, and don't want to go buy another :-)

I have some onion seeds, I guess I should start them now under growlights?

Glaswegian: I'm sorry not to have noticed your message sooner. Went and got the container. The high middle number formulation is specifically designed for a really strong root system, apparently. When we put the tomatoes out, the stem is bigger than a pencil - and there are little root nodes along the stem, too. We plant them nice and deep - the plant puts out new roots along the stem and this makes the plant really solid. Another thing we do is wrap the stem with a bit of aluminum foil where the stem meets the soil. This prevents the dreaded cut worm - which can kill your plant overnight. We do this to our peppers and eggplants too. I understand some people use toilet paper or paper towel rolls, but we stick by the alum. foil method. Hope this is helpful.