So many things to consider. If you direct sow seeds that are correct for your area, ask "will the seeds germinate and grow strong enough to be prepared for the harsh cold"? Or should you have planted them a lot earlier to get established?
One way is to set a budget; buy as many seeds as you can get for that price. Then plant the seeds. If they live, good. Transplant them where you want them in the spring; if they die then plant earlier. If they die, try different varieties. Something will work.
Seed gardening is all about experimenting any way.
IMHO Never lay out your seed plan and expect the plan to work as you envisioned. Not with seeds. But then that's why I love seeds. You never know what will happen.
Finally, I have often tried 10-20 new things a year. If I get 2 winners I am happy. Because in 10 years I will have 20 winners that love my yard. You finally reach your peak. This year I am only trying one new thing.
Tip: Get your seeds for your area on the Seed Exchange on this site. Even if you have to buy seeds to exchange. Ask what others do to make the seeds succeed that you are exchanging for. Trade with your local traders for greater success.

Sow the seeds outdoors at the end of winter, thin if you are into it, to give them room to grow. You can leave some seedlings in small clumps.

Those early flowers will overlap with your summer bloomers, so at some point they will have to be growing at the same time. You can sow the later annuals directly in the ground around the bulb foliage.

Yes, you can start annuals after you rip out the early stuff. Once it's really summer, annual seeds take off fast but need more water and protection from chewing bugs like grasshoppers.

Seed starting can be a whole other hobby. You're doing the right thing by reading up on it all. As you experiment, take notes and see what works in your garden. Each location presents different challenges.

thanks for the great responses! I appreciate it.

I have planted a seed from my lemon bush (I think it is a Meyer lemon bush). It grew really nice, even the winter didn't harm it, but after 3 years, having grown to over a meter tall, it still did not fruit. Any info on this is much appreciated.

Kiwichristel

Hi Kiwichristel,
Someone might answer you here, but you might want to post the same question in the Citrus forum.
Good Luck
Bob

Kiwichristel, it typically takes 3 - 6 years for a lemon grown from seed to be mature enough to begin to bloom and bear fruit. Yours is on schedule.

if you are making a "WILD" garden, with no order, no priorities then you would just broadcast the seeds late winter or early spring.

But if you have a vision to have a garden by design, then you either sow the seeds in flats/pots and the transplant them in the garden, according to size, color of flowers, flowering time ..etc. Or if you can afford buy the plants from nurseries.

In a newly started perennial garden you can add some annuals to complement until the perennials grow and fill the space. But eventually, you should not plant any annuals in a perennial garden. UNLESS you know exactly the vacant spots.