Blossom-End Rot in Square Foot Tomatoes

Black bottom rot = blossom-end rot from inconsistent watering and/or calcium deficiency. Calcium is hardest nutrient for young roots to absorb.

Complete Solution

• Water deeply 1-2x/week (not shallow daily)
• Add crushed eggshells or 1-2 tbsp Epsom salts per planting hole
• Mulch heavily with straw/dried grass
• Epsom salts (magnesium) improve calcium uptake efficiency

Problem self-corrects after first/second fruit set. Prevention beats correction — build calcium into soil annually.