When you plant head lettuce, kale, chard, collards, or a number of other seed sown crops, you always have to thin them out. Don't throw them into the compost pile though. Small immature kale, (and shown in this photo) chard and romaine lettuce, are wonderful in salads. They are sweet, tender and perfect for any type of salad. Just because they aren't mature, or full size, doesn't mean they're not good to eat. I want my kale, collards, chard large, but to get them that way i have to thin the crop so they're not too close together. I can still benefit from what i planted, and not waste them, but eat them! 

What's mature and ready to eat are leaf lettuces and spinach. The photo above shows my spinach and a leaf lettuce called red sails. When you plant early, you can harvest early and have fresh homegrown produce that much sooner. I planted my spinach and red sails lettuce back on March 22nd. I usually plant it even earlier but we still had snow on the ground. I've been harvesting it for the last 10 days or so. Planting as early as you can, as soon as the ground can be worked, gives you food to harvest as soon as you can.