Deck gardening-My plants are slow at producing. Any ideas ?

What plants do you have,lighting conditions,watering etc?

Used coffee grounds and ground egg shells sprinkled around the soil at the base of the plants. Do about once a week. My grandma always did that around her fruit trees, flowers and garden plants.

Assuming your plants are in pots. Yes, they can grow slower, make sure you fertilize regularly and that they get enough water if hot.

Epsom salt

Also cooled off coffee

Fertilize once a month and make sure that you water religiously

It may be the weather. I am usually up to my elbows in ripe tomatoes this time of year and have not had a single one ripen so far. MN is cooler than normal, is it not?