Carrots - can be pulled when they are as big as your finger, they will be sweetest then. Also look for a carrot top that is bright orange. Cut their tops off if your not going to eat them right away.
Corn - the husk should feel full, look for the plants silks to be dry and brown, greenish near the cob. Cut a slit in the husk to do the kernel test; pierce one kernel with your fingernail, if the liquid is clear it's not ready, if there is no liquid the corn is over-ripe and if there is milky liquid it's just right. Pick in the morning for ultimate sweetness.
Cucumber - look for the flowers to fall off of the cucumber, it should be dark green and large enough to use; pickling varieties should be 2-6" and slicing varieties should be 6-10".
Eggplant - the skin should be smooth and shiny but firm, most varieties will be more than 6", the smaller the eggplant the better the flavor.
Peppers - pick when peppers are big enough to use, certain peppers are not completely ripe until they turn their final color. If you pick certain peppers before they turn red that plant will continue to set new fruit.
Potatoes - new potatoes can start to be harvested anywhere from when the plant flowers to two weeks after the flowers have died. For non-flowering varieties this is about 10 weeks after planting. Dig out a few new potatoes for that nights dinner and replace the soil. For your final harvest and storage potatoes dig up the plant carefully when it's dry and after the foliage has died back. Leave the potatoes out in the sun to dry for a couple of days.
Snap Beans - look for beans that are straight and thin as a pencil, pick in the morning (only if plant is dry) when they are at their sweetest. The seeds should be barely visible in the pod and it's tips should be soft.
Sweet Potato - usually ready 100-140 days after planting, harvest when plant dies down on dry days before the first frost. Be careful to avoid damaging your potatoes when harvesting and cure a week before storing. Rinse very gently if absolutely necessary.
Watermelon - look for the tendril nearest the fruit to turn from green to brown, also look for the bottom of the plant to yellow.
Winter Squash - look for the vine to die down and the stem to dry, the skin should be hard making it difficult to pierce with your fingernail. When cutting, leave 1" of stem. Buttercup and nut varieties taste better after sitting in the sun for two weeks after harvest as does Spaghetti Squash which is usually ripe when the stem cracks.
