Grafting or container growing would just about guarantee success.
Trying to dig out and replace the soil is a long shot.
And if the problem(s) are actually in your native soil, which they very well may be, you'll be right back where you started.
At least you have time to observe what the rest of your plants do as this season progresses, consider options between now and next spring, and hopefully harvest tomatoes for a bit longer before the plants start dropping.
|