I would encourage you to read my blog on upright geraniums here first. That blog is a great primer on correct watering practices.
So here we go. These trailing beauties love full sun but prefer partial sun especially during the summer heat Daily watering and weekly fertilizing are critical for proper blooming. But the main reason for timely watering is to avoid edema, which is ruptures on the underside of leaves and looks like this
This rupturing happens when plants are allowed to dry too far and then watered. The uptake of water then bursts the cells under the leaf surface. Another greenhouse grower explained to me that if a trailing geranium uses a certain amount of water each day you need to replace the same amount. Imagine if you did strenuous activity in the summer without drinking any water, but then drank a large bottle of water afterwards. Your stomach would hurt. So water your hanging basket daily and make sure some drains from the saucer!
Pruning of longer branches through the summer will encourage more growth producing more flowers. Depending on the size of your hanging basket, select 2 or 3 stems and snap off 1/3 of the length (growing tip towards the basket) then 2 weeks later prune 2 or 3 different long branches. This constant pruning is great for a full basket (we prune constantly in the greenhouse to avoid gangly, thin looking plants). Spider mites are the most destructive pest of this plant. Pick off a few newer leaves and check the underside with a magnifying glass looking for tiny spiders. Poke them with a pencil point to see if they move. If you notice many spiders purchase a spider mite spray at a store (Bayer Insecticides) or whatever you are comfortable with. If you wait too long before checking and notice spider webbing, it’s too late and you should discard the plant.
Of course using our liquid fertilizer is recommended especially the #21 shown here.
Click on picture for our fertilizer!