Does anyone have advice on how to keep flowers in a flower box alive?

Hi! I have petunias, geraniums and sweet potatoe vines in a flower box right outside my window. It's in an area with heavy sunlight and a good amount of heat. I try to water them every day, but they always seem to dry out! Is there a trick to keeping them alive and well? Without overwatering?
Does anyone have advice on how to keep flowers in a flower box alive?
Proper drainage is important. If the soil is too dry, it could be that either there is too much drainage, wrong type of soil, or too much heat. Since we are in the middle of the summer months, my bet is that it may be a combination of all three reasons. Check the drainage holes. If the flower box is one that sits on a ledge, you may need to put a container underneath to prevent all the water from quickly running out. Second, check the soil. If the soil is not absorbing the water properly, it can also be adding to the problem. Invest in some new potting soil. You can tell fresh soil in the way it absorbs the liquid. It acts like a sponge. It may be because the old soil has lost its nutrients. Lastly, in the summer it is very important to water plants regularly and more frequently because heat will cause the water to evaporate faster.
Reply:Make sure you drill holes in the bottom for good drainage. I heard on TV to put the insides of a babys diaper in the bottom to help hold moisture. I have never tried it.
Reply:You can try putting a pan or something underneath the pot, then when you water them and the water runs out it will run out into this pan, when the soil starts to dry out it will start sucking the water up into the soil and keep them wetter.
Reply:Make certain that your flower box drains from the bottom. It should have a reservoir tray beneath, water it there if at all possible. This should also prevent over watering. Adding a TBSP sugar per qt of water also helps.



Good luck!
Reply:I have the same problem. I have more than one. I rotate from full sun to a place with partial sun for a day to two then back to the sun.
Reply:There are soil additives, gel looking stuff, that retains lotsa water without being too wet for the plants. Window boxex dry out quickly on a sunny day.
Reply:Spend the extra money to get a soil that will hold water better. Drying out is a big problem with flower boxes because they lose a lot of water to evaporation since it's suspended in the heat rather than the ground where the temp is more steady.