Carrots take a long time to be fully done; 100 days or so. Would not recommend putting those in an area where you want to grow warm-weather crops. Peas most likely would work. What I've typically done is make a row of peas on a fence and after it begins to get warmer, I'll start cucumbers on it. So the peas will produce and grow as the cucumbers are beginning to sprout. Works quite well. Spinach is a cool-weather crop and should do just perfect for your rotation plan. Onions will not; they also need full sunlight; the larger the onions, the larger the bulbs. They also take 100 or more days for northern varieties. I cannot comment on kale, beets, chard, or parsnips since I don't grow those. Here is a link that might be useful: My Garden Blog

My city and county does have a composting center. You can not haul leaves and grass clippings to the dump. They also have a limb burn pile. Every year I haul truckload after truckload of the compost back home and spread it on the garden. It is free and if you go on the right day, they will load you with a skid loader. Our local grocery store gives our tiny zoo produce that is past its prime. Is it bad, no, just no one will buy it. It save them lots of money, the zoo that is. Why is it the policy of all companies to not give away bad produce and scraps, Liability Insurance! If they gave it away, then they could get sued if the person accepting it, ate it and got sick. Gotta love lawyers!

What to plant following what was planted depends. Cool season plants sucha as peas can be followed by tomatoes, peppers, etc. Cool, and long season plants such as the cabbage family will be there for the full growing season most places. Beans could follow lettuces which could then follow the beans. Lay out your garden and look at what you want to grow and which need to be in early and will fade out in heat. Then look at what you want to grow that should be planted during really warm weatehr and see where it fits in the total plan.

Hello I;m on the southern coast of Maine and I have already direct seeded outside spinach, lettuce, peas, radishes,parsips, and shallots. My spinach and lettuce is already up. And I will continue to seed directly those vegetables every two weeks until June so that I have a steady supply of them. They are cool weather crops. Next week I will start my potatoes. Of course, I am already harvesting my chives wich are full of good minerals. Other nature's way of giving us a head start on something green before the first spring crop comes in. My egptain onions come up even before the chives are ready for harvest. so that is to good things to have in your garden. Plus once planted they come back year after year and require no work. In early May I will set out seedlings, small plants, that I grew from seeds inside, under lights, or some I get at a nursery: cabbage, broccoli,cauliflower and I will also at te same time direct seed. carrots. swiss chard, and kale. I will continue to direct seed the carrots and swiis chard every two weeks through mid July so I have a nice on going supply. The last frost date for Maine is usually considered to be memorial weekend. Some people claim you can start planting warm weather crops after the full moon in May. Many people will plant mid may while watching carefully for frost alerts and cover up their crops with sheets or some sort of covering if one is predicted. Some people cover their crops with cut out milk bottles over individual plants to keep them warm during a potential frost. Usually sunflowers, pumpkins, winter and summer sqaushes, eggplants, green bell peppers, watermellon, corn and tomatoes are not planted until early June, they need warm soil, as well as warm weather to thrive. raised beds do warm up faster then the ground and you can put clear plastic over your beds for a few weeks to help the soil heat up. It all can be overwhelming at first. But every year you will learn and master something new. What a great project for the kids and you. I wish you a bountiful harvest. READ as much as you can. You will slowly start to soak in all the information and learn to apply it to your garden! Remember if you don't feed your soil, if your soil is NOT feed the nutrients it needs, your crops will not thrive. Good soil is the foundation for a bountiful harvest. So make sure you give your soil what it needs so your plants can grow .