I agree with ohiofem, just make sure you cut the right one out when that time comes :) Also, make sure you are extra diligent with staying up on the watering when they are in containers, if you give them too much water in one shot after not watering for a short period of time, you may risk the splitting the melons. I grew some crimson sweets last year in containers smaller than yours, and I got a few ripe melons, but they were far smaller than they should have been, probably due to crowding in the root zone. A couple also split because if forgot to water one day and then saturated them the next, a couple of the melons split within hours.... they were ripe though (or close at least) and I discovered them soon so I ate them anyway:)

I don't have my seed packets handy right now so I won't be able to be specific, but I've been starting impatiens from seed for several years now and haven't noticed that they take any longer than it says on the pkt. of seeds to germinate. I think it's around 10 days, but mine normally germinate more quickly because I put the container about 4' away from our wood stove. Our last frost date is around May 25, but yours may be a little earlier even though you are also in zone 5. I would suggest you count back 10 to 12 weeks from your last frost date and sow the impatiens seeds then. For me that would be mid March. That should give you plenty of time to grow them out to the size you want before planting out. If you want bushy plants it's important to keep the light source about 4" above the plants at all times. I use grow lights and move the lights up as the plants grow. If you are going to grow them in a greenhouse I guess they would get enough light that way too. I don't recall pinching back my impatiens as they grow slowly. I use soiless potting medium to start my seedlings and fill small containers, about 5" x 9" x 3" to the top with the seed starting mix. You can use other type containers but be sure they have good drainage holes in the bottom. Be sure to moisten your soiless mixture first as stated on the bag so it is just slightly damp. Then after sprinkling the tiny seeds on the damp mixture, I press in lightly and place the container in a pan of water until it feels wet to the touch on top. Then drain it in the sink for about 15 min. Then I label the container and place it in a plastic bag. Fold the excess bag under the container, cut a few slits in the top of the bag and put the container in a warm place to germinate. I would say about 75 degrees would be good. If it's not warm enough, it will take longer to germinate. Once you see the tiny sprouts coming up, remove the plastic bag and put the container under lights, if that's what you're going to use. I use a diluted fertilizer, 1/4 tsp. to a gallon of water, every time I water, and I ALWAYS water from the bottom by putting the container in a pan of water. An old 9 x 13 baking pan works good for this. After the seedlings have two or three true leaves, that's the ones that come after the first two, then I pick out the seedlings into individual plastic cells using Pro Mix potting soil. I continue then to grow them under the lights, watering them from the bottom, and fertilizing as stated before, until it's time to plant them outside. If you're not familiar with how to do this, you can find the info in a gardening book at your local library. I've seen it in several that have to do with propagating. When your ready to plant them outside, be sure to harden them off first to acclimate them to the outdoors. That's another subject and you may already know abut it so I'm won't elaborate. Hope this helps.

If you are going to add lime and fertiliser after stripping off the present plant cover - also add in plenty of humus by way of compost of some kind. If it is available to you, spent mushroom compost can be useful for bring a soil toward neutral and it encourages a different population of soil creatures. Whatever you add, make sure it's well-rotted, or nearly so. It will be effective more quickly. You can often notice the changing soil pH by looking at the weed species growing now - and about a year later, when you've done your amendments and added more humus. Certain species, such as English daisy and sheep sorrel, are clear indicators of acidity. (It's cheaper to look for weeds than get the soil tested...) Remember, if you're planning to grow plants such as azaleas, they won't be too pleased with a lot of lime in the soil. There are also vegetables which prefer soil on the acid side, although most plants will grow in the neutral range.

I would say yes to potting up most things. For example, I started some lettuce seedlings in a 72 cell tray in mid january just to see if my lights were strong enough to grow them from seed. I harvested the lettuce last week because it was growing all over the place and about 7" tall! When I pulled out the plugs from the cells, the roots were horribly root bound and wrapped around many times. I didn't think it would be that bad because they were still fairly small...not micro greens, but not a full head leaf lettuce like you get at the store. Based on that observation, I think I will be potting up most everything at least once. I read about using clear deli containers, and I think that will work better than buying the 3 or 4" pots from the garden center. I plan on going to GFS to pick up a sleeve of the deli containers. They are only a few bucks, and you get either 50 or 100 of the containers. I'm just going to poke a few holes in the bottoms for drainage and use them. As a bonus, it will let me see if they are starting to get roots around the edges since they are clear. I'll probably go with the 32 oz size since I'm not too sure what the weather is going to do and I can keep most of the plants in that size for longer if need be.