Balcony railing planters

[Bonbon]

Hello I have some balcony railing planters.. that fit over the railing and have a part on either side.. like pic attached. However I've tried growing petunias or vinca in them and they don't grow well. I feel the pots are two deep and these flowering plants arent deep rooted... is there something I can put inside the Base to make them shallower or are there specific types of plants to grow in them... any help appreciated. Thank you

 

[ErnieCopp]

I am not a container grower, but most plants grow if they are not too hot, not too cold, and have the right amount of water. I suggest you buy a moisture meter, and keep the soil at the right moisture level. If they wilt with plenty of moisture, it is just too hot for them in that location, and the roots cannot keep up with the transpiration. I do not think the shape of the planter has much to do with it. The dirt on the ground is pretty deep, and does not cause a problem there. Plants all keep their roots near the surface where the warmth and moisture is.

Plant them at the same depth they were in the containers when you bought them. If you are planting seed, those can be planted too deep but again, the overall soil depth below the seed is not a factor. Go on Google and you can find explicit instructions on how to grow every plant and flower.
Good Luck,
Ernie