The interwebs are full of Imbolc rituals full of seed plantings. Regardless of local conditions, regardless of local climate zones. Regardless of the fact that, in most of Europe/North America, the only seeds you'd plant now are onions (and that's not necessarily the occult correspondence most folks are after just now, ya know.) Regardless of what's actually going on in their local land base. Yeah, the seeds represent changes in your life - but working outside of nature isn't all that Pagan/Witchy.
Doesn't work for me, but okay, if that floats their boat (that was said in my best Bawltimore accent, not a Boston accent, hon), let's go into what has to be kept in mind when doing seed work.
Planting seeds, and having them come up soon, can be a great psychological boost. So, while parsley is a seed that can be started now - don't use it. It takes forever to sprout, even if soaked before planting. One of the parsley seeds I planted outside last spring ... didn't sprout until fall.
How are you with houseplants? If you tend to kill them all - this type of ritual isn't the type for you. What you plant isn't likely to grow any better, and if you are relying on a magical bond between the plants you are starting and your outcome - you may well have a problem.
Does what your planting actually grow in your area, and if not, does it grow well indoors? Will the plant last as long as it takes you to make a real change?
Nothing grows well unless you've prepared the soil beforehand. Ideally, you'd have been doing that since Yule. Gathering materials, clearing away known obstacles, clearing room, carefully identifying goals and steps along the way, etc.
Have you taken care of this step?
Planting - the official starting - of the process is great. But there's a long time and a lot of work between planting and harvesting. What are you plans for dealing with early frosts? With weeds? With insects and disease? Spiritual goals have these things, too. And just doing the planting isn't really enough to get past the vice of Malkut (inertia).
How long can you go without getting the harvest you expect? We all know the meme "Oh, Lord, grant me patience, and give it to me NOW".
Are the seeds in tune with your spiritual goal? Lavender sprouts well, but may not be the best to plant if you're after physical fitness, or business success.
Will you need help with harvest? Okay, most of you aren't planting acres of wheat, but still ...
This isn't an exhaustive list, obviously. Just stuff to keep in mind.