You need to water upside-down tomatoes once daily during normal weather. When temperatures climb above 85°F (29°C), you should water twice a day. These hanging buckets dry out much faster than pots sitting on the ground.
I learned my upside down tomato watering schedule the hard way during a hot summer a few years back. Temperatures hit 95°F (35°C) for almost three weeks straight. My plants wilted badly with just one daily watering. I switched to hitting each bucket around 7 AM and again at 6 PM. That double watering routine saved my crop. The soil never dried out and my plants stayed healthy all through the heat wave.
Your hanging buckets lose water faster than ground pots for a simple reason. Air flows around all sides of a hanging container. Wind speeds up water loss from the soil surface. It also pulls moisture out through the stem hole at the bottom. Pots on the ground have cool earth below them. That dirt acts like a shield against heat. Your hanging bucket gets warmth from every direction. Heat bounces up from pavement and walls too.
Rutgers Extension confirms you may need to water container plants 2-3 times daily in hot weather. The smaller your container, the faster it dries. A 5-gallon bucket in full sun can lose a full gallon of water on a hot windy day. Watering hanging tomato plants takes more attention than ground gardens. You have no deep soil below to draw extra moisture from.
You should check your container tomato moisture before each watering session. Use the finger test to know for sure. Push your finger one inch into the soil near the bucket edge. If that top inch feels dry, your plant needs water now. If it still feels damp, you can wait a few more hours. This simple test keeps you from both underwatering and overwatering your plants.
Keeping a steady watering schedule prevents blossom end rot. This ugly problem shows up as dark sunken spots on your tomatoes. It happens when soil moisture swings wildly between too wet and too dry. Your plant struggles to take up calcium during dry spells. The bottoms of your fruit turn black and ruined. You can't fix affected tomatoes. You can only prevent the problem from hitting future fruit.
Water your bucket until liquid runs out from the stem hole at the bottom. This drainage tells you moisture reached the full root zone inside. Quick splashes on the top leave dry pockets deep in the container. Your roots suffer in those dry spots even though the surface looks wet. Pour slowly over 30-60 seconds to soak the soil all the way through.
Morning watering gives your plants moisture before the heat of the day arrives. Evening watering helps them bounce back after afternoon stress. Pick times that fit your daily routine and stick to them. Your tomatoes will reward your steady care with healthy fruit that ripens without those ugly black bottoms ruining your harvest.
Read the full article: How to Grow Tomatoes Upside Down Successfully
