Brandywine tomato leaves and petioles not healthy
I have a container-grown Brandywine plant but the lower leaves are leathery, drying/dying at tips and along edges near tips.
Petioles are brittle and easily accidentally detached from plant stem. Plant has grown about 6 inches in height since transplanted from pot to 5-gallon container 28 days ago.
Plant is approximately 20 inches tall.
The upper leaves are leathery, but supple and deep green, no yellowing/drying/dying of leaf tips or edges.
Anyone have suggestions to get the plants back to health?