“I like this place and could willingly waste my time in it.”
― William Shakespeare
Now that your plants are in your tower it just a matter of feeding, training, and pruning.
You need to change your nutrient solution every ten days or so. To do this, turn on your pump and connect a hose to the top of the tower. Pump out as much water as you can. Dilute the remaining solution with more water and pump it out again. Now fill your bucket all the way up with water. Mix the appropriate amount of powder nutrient (or whatever you are using) with water in a small container mix it up until it's dissolved and slowly add it to the top of your tower and leave the tower on for at least 15 minutes to make sure the nutrients and water are well mixed.
DO NOT USE PLANT FOOD CREATED FOR SOIL PLANTS! Soil food will kill your hydroponic plants. If you are using the plant food I have provided you want to use one teaspoon nutrients per gallon of water. Start with 1/2 strength for the first cycle so you don't shock your plants. When you need to buy more, if you want to use the same food I've provided, it's Maxi-Gro by General Hydrponics. You can find it at most quality hydroponics shops, or on Amazon. Your local hydroponics shop will be a great resource, so if you have one it should be your first choice. If you have one tower, a single 2.2 Gallon bag should lasy you the season.
Alternately you can keep a spare bucket full of water a couple days before the nutrient change, mix in the nutrients, and with an additional pump, pump your solution into the spout opening in your bucket lid. I do it this way so if the tower bucket ever gets low I can easily top it off with premixed solution. If you don't do this you will have to top off your tower when your nutrient solution gets low with a hose and add nutrients by approximating how much water you added.
If you are growing vining plants like tomatoes, squash, cucumbers, etc, you will want to loosely tie young weak vines to your tomato cage, or make sure they are resting on horizontal cage wires. As your plant grows you may need to remove and add ties back. You can also create additional supports by tying gardening wire between different parts of your tomato cage. When plants bearing larger fruits or vegetables start to become weighed down, it's a good idea to tie branches to supports above them. This will keep branches from breaking and keep your plants in great shape.
Tomatoes need to have suckers removed. Suckers begin as small branches that sprout out between where a leaf stem meets the main plant stem. They typically sprout leaves and stunted tomatoes, if anything. They suck energy from the main plant and will cause your tomatoes to grow to a smaller size. The fewer branches you grow, the better and larger your tomatoes will grow. You will receive a smaller quantity, but it will leave space for your other plants. You can pinch the suckers off with your fingers, this method minimizes damage to the plant. This also helps you keep a neat plant. If you decide not to do this, your plant will still be fine, but it will be a wild bushy mess in no time.
When days start getting shorter and cooler it's a good idea to prune off younger leaf systems to allow more mature parts of the plant to get sunshine. When the season is coming to and end, remove any remaining flowers that have not set fruit. This will signal to your plant that it is time to ripen everything left before the plant dies.