In order to revitalize Waffle Island you need to rebuild the rainbows. Before you can do so, you'll need to get the Quilt from Hamilton. The left-side will be given to you by the mayor after you have earned 2000 G or more. The right-side will come from fixing the clock tower in Waffle Square, which requires you to talk to Gill, then Dale, and finally Hamilton again in order to get the Clock Tower Key.
Once you have both pieces of the Quilt, you can awaken 3 of the Harvest Sprites by sprinkling the flowers with your watering can. Ben is the blue flower near the pond in Maple Lake, Daren is the green flower under the tree in Waffle Square, and Allen is the red flower northeast of the animal barns at Brownie Ranch. Each sprite will give you a Rainbow Recipe, which consists of 5 different items you'll need to collect. You don't have to do each recipe one-at-a-time; you canh work on the first 3 all at once.
When you have collected the 5 ingredients for a complete recipe, put the items in your rucksack and sprinkle the Harvest Sprite. It will take your items, sing a little song, and create a rainbow.
Finishing Daren's rainbows will gain you access to Gull Island, where you can get another recipe from the yellow Harvest Sprite, Collin.
Grilled Eggplant - This item is only available in the Fall season. You can grow the Eggplants yourself (285 G a bag) or simply just buy a Perfect Eggplant from Ruth at Souffle Farm for 210 G. The next thing is to get the Matches from Simon's shop for 600 G. Then take the Eggplant (any quality), the Matches, and find one of the piles of firewood, either at Cream Beach or the beach in Caramel River District. Use the Matches on the wood to light a Bonfire, and then "use" the Eggplant on the fire.
Char - The fish can be located in the pond at the base of Caramel River's waterfall.
Green Herb - These are very plentiful, and you can usually find them in Waffle Town, Praline Forest, or around Brownie Ranch.
Plain Omelet - There's two ways to collect this item. You can make the cooked dish yourself if you combine an Egg, Butter, and the Frying Pan kitchen utensil. The easier way is to just buy it, which you can do at the Spring and Summer Flea Markets. On the 22nd of the season, go to Waffle Square and talk to Simon. You can buy a Plain Omelet for 240 G.
Good Tomato - You can buy Tomato Seed from Souffle Farm during the Summer season for 225 G a bag. Plant the crops in your field and take care of them until they produce. You need a "Good" quality Tomato, not a "Decent", "Perfect", or "Shining". The other option is to wait until the Fall 27 Harvest Festival, where you can buy the Good Tomato from Craig for 165 G.
Grilled Yam - This is just like the Grilled Eggplant from Ben's recipe. Either grow the Yam from seed (135 G) or buy it from Souffle Farm for 180 G, but only during the Fall season. Then roast it with the Bonfire. The other option is to buy the Grilled Yam from Maya for 165 G during the Spring and Summer Flea Markets on the 22nd of the seasons.
Carp - You can find this fish in the Caramel River and in the pond at Maple Lake.
Good Herb Fish - This Oven recipe can be made with any herb or fish, but the ingredients must be worth between 300 G and 600 G if you were to ship them. You can use more than 1 fish. Some suggestions are:
Common Seashell - You can find the shell by looking around the beach in Caramel River District or along Cream Beach in Waffle Town. The shell can appear all year long.
Apple - Besides growing your own Apple Tree, which takes 50 days to grow and only produces fruit in the Fall, you can buy this item from Simon at the Spring and Summer Flea Markets for 225 G. The third way to find an Apple is to buy it from Souffle Farm during the Fall season.
Saury - You can catch this fish in the ocean off of Waffle Island during the Fall or Winter season. There isn't any other way to collect this ingredient.
Blue Wonderful - An easy item to get from the mines. Look for the blue-colored crystals as you are descending down the mine floors and smash them with your hammer. You may receive a Blue Wonderful. Some of them will have sparkles, indicating that they can be refined for a good jewel, so try to find one that doesn't have sparkles for the rainbow recipe. The sparkling ones can be refined by Mira so you can ship them for gold.
Perfect Spinach - This crop can not be purchased at any festival or ship. You must grow the rainbow ingredient yourself during the Fall season. Buy the seeds from Souffle Farm for 75 G a bag. If the crop soil on your farm is not very healthy, you might also be able to buy some Fertilizer as well.
The fertilizers will appear at Souffle Farm after you have spend at least 5000 G at their store. Buy either the 1-season or 2-season fertilizer, till the soil in your field, put down the fertilizer, and then put down the Spinach seeds. The crop should be ready to pick in about 5 to 6 days.
Banana - Once you revive Ben and Daren's rainbows, the winds will calm so Pascal can ferry you over to Toucan Island. On the island you can find wild-grown Bananas or you can buy one at the Pineapple Inn for 150 G.
Red Wool Yarn - This is another item you'll have to produce yourself. You can get wool from sheep, which you can buy from Brownie Ranch for 4200 G. After a season it will be an adult, and you can clip its wool every 4 days.
You then need to get the Yarn Maker machine from Simon for 4500 G. The Yarn Maker comes with a Dying Pot to turn your yarn different colors by using flowers. Different flowers will produce different colored dyes. You need a "red" flower, so the plants you will be looking for are:
Put the Wool Yarn (any quality) into the Dye Pot inside your barn, and then select the red-colored flower from your rucksack when prompted.
Toadstool - Even if you go to floor 2 of the Ganache Mine, you'll find this orange mushroom. This is very easy to find and will be in the mine all year round. You can also find it around the base of Gelato Mountain.
Wood Fish - You can't catch this fish until 1) You have received the Rainbow Recipe from Alan, and 2) You have to complete Ben and Daren's recipes. The fish can be found in the Harvest Goddess' pond in any season, between 7:00 pm and 5:00 am. It is very rare, so you just have to be patient and keep trying.
If you want to stay at the pond until the next morning, try to bring some Stay Awake or Super Stay Awake with you. The potions will ward off the drowsiness that occurs once you've been awake past 6:00 am. If you don't have the potions you will be stuck at a slow-walking pace and have to drag yourself back home to sleep. You can buy the potions from Irene at the Meringue Clinic for 375 G and 525 G.
Green Bell - This item can be grown during the Winter season if you buy the seeds from the Pineapple Inn on Toucan Island for 165 G each. The other way to get the flower seed is to buy it during the Harvest Festival on Fall 27. Either way, you have to grow the crop yourself.
Ostonnaise - This is made by putting an Ostrich Egg into the Mayonnaise Maker. You can also buy it from the Spring and Summer Flea Markets from Maya for 480 G.
Carrot Cake - If you are currently in Spring or Summer, you'll have to make the cake yourself by combining a Bread Fruit, Egg, Carrot, Butter, and Milk with the Oven cooking utensil. If it is currently Fall or Winter, you can buy it at the 22nd Flea Market from Elli for 900 G.
Tuna - This large fish can be caught with a level 4 or 5 fishing rod if you are casting at full power from Cream Beach on Waffle Island. The other, and easier, option is to take Daren's rainbow to the Gull Islands. On the eastern island (the one with the Penguin) you can catch the Tuna without having to use a high-level fishing rod.
The Tuna is available in the Spring, Fall, and Winter seasons. The weather must be either sunny or cloudy.
Snowflake Flower - During the Spring and Summer seasons, you can buy the flower from Candace at the Flea Market for 120 G. If it is Winter, you can grow the flower yourself by buying the seeds from Souffle Farm for 150 G, but only if the farm is at 3-stars. If you are in the Fall season then there's nothing you can do for the moment.
Perfect Honeydew - You can buy this item from Souffle Farm for 690 G during the Summer season, or you can grow it yourself. The seeds cost 735 G per bag and you need to produce a "Perfect" crop. Using Fertilizer is recommended.
Lapis Lazuli - In the Ganache (or Gelato) Mine you'll find blue crystals that can be smashed to uncover Blue Wonderfuls. The wonderfuls you are looking for must have 1 "shine" on them. You can see how many shiny-marks a wonderful has by looking at it in your Rucksack.
After you collect your Blue Wonderfuls, go to Mira's counter inside the blacksmith shop. She will refine the stones and hopefully discover the jewel you're looking for.
Red Honey - You will need to grow red-colored flowers. In the morning after the flower has bloomed, you might discover a little bee flying around it. If you pick the buzzing plant you'll have a chance of getting Decent Honey, colored Honey, or Royal Jelly. There isn't a guarantee that you'll find a bee every morning, so don't pick the flowers once they have bloomed.
The flowers you can grow are the same as those needed for the Red Wool Yarn ingredient: