Yes, you can use 10-10-10 fertilizer on your cucumbers. This type of fertilizer is a complete fertilizer, meaning it contains all three of the major nutrients - nitrogen, phosphorus and potassium. The numbers on a fertilizer represent the percentage of each nutrient by weight in the bag. So, 10-10-10 fertilizer has 10% nitrogen, 10% phosphorus and 10% potassium.
Cucumbers are heavy feeders and need lots of nitrogen to grow well. Nitrogen helps with leaf and stem growth, so if your cucumber plants are looking yellow or stunted, they may need more nitrogen. You can side dress cucumber plants with additional nitrogen during the growing season by using a manure tea or composted chicken litter.
Phosphorus is important for root development and flowering. Potassium helps plants resist disease and promotes strong stems.