Can you use miracle grow on raspberries just before picking?

i use miracle grow vegetable fertilizer on all my producing plants. i have about 40 strawberry plants and use it through a water feeder when i water. i lightly fertilize them about every 2 weeks. the plants are healthy and very prosperous. the down side is that the added fertilizer promotes runner growth which can lead to a smaller berry and crop. i fix this problem by cutting the runners off while the plant is producing, and let them grow after i harvest.