The best time to harvest your garden is early morning. Your crops are cooler and have a higher water content which means those veggies will have crisper texture than during the day when the temperatures are warmer.
Broccoli - Harvest broccoli in the morning, when the heads are large and fully developed.
Carrots - You can harvest them when they are young and tender as often as you need them.
Celery - Harvest them when you’re ready to eat fresh.
Cucumbers - You can pick cucumbers often while they are young and they will continue to crop.
Corn - Harvest when the ears become rounded at the base and the silks at the top turn dark brown but don’t let them dry out. Peel back tusks you can tell matured corn cobs because they will be filled with plump kernels.
Eggplant - Once eggplant reaches that rich dark purple color it is ready to pick. It should be dark and shiny.
Kale - Harvest Kale by picking the outer leaves when the plants are sturdy and well established.
Lettuce - Pick lettuce in the early morning while it’s cool and the leaves are still crisp.
Onions - Harvest when the tops begin to droop and dry.
Potatoes - Harvest when the tops begin to droop and dry.
Peas - Eating them raw in salads or for a summer snack you’ll want to pick them young. If cooking them you can wait a while longer.
Peppers - It’s okay to pick them when they’re green because they will ripen once picked. Or you can leave them to ripen on the bush then pick when ready to eat fresh.
Pumpkins - Harvest pumpkins when they have a deep orange color and the shells are so hard that they can’t be pierced or indented with a fingernail.
Tomatoes - You can pick them when they still have some green, then set them on the counter or in front of the kitchen window to ripen after being picked. But if you want that sun ripened flavor you’ll want to pick them when they have no trace of green.

Great harvest list! Zucchini spaghetti sounds like a good idea for dinner tonight.