Your tomato dark spots cracks come from one of three causes. Fungal infection, water stress, or nutrient transport problems each leave different marks. Each tomato fruit problems type needs a different fix. Knowing which one you have helps you save the rest of your harvest.
I used to throw away any tomato with dark spots or cracks without thinking twice. Then I learned to look closer at what I was seeing. Now I can tell fungal spots that need worry from cracks that just look ugly but taste fine. This skill has saved me pounds of good fruit over the years.
The cracked tomatoes cause most gardeners see comes down to water swings. When dry soil gets a big drink all at once, the fruit swells faster than skin can stretch. The skin splits in lines from the stem or rings around the top. These tomatoes are safe to eat right away before rot sets in.
Anthracnose tomato spots look very different from cracks. This fungus makes sunken dark areas with a pink or orange center on ripe fruit. The spots grow and spread to other tomatoes in your basket. You'll see this most after warm, wet weather.
Blossom end rot shows up as a dark, leathery patch on the bottom of fruit only. Many gardeners think they need calcium to fix this. The real problem is usually water though. When plants can't move water up to fruit tips, calcium gets stuck too. Even calcium-rich soil won't help if watering is uneven.
To prevent cracking, keep your soil moisture steady all season long. Mulch around plants to slow water loss between rain. Water before soil dries out too much instead of waiting until plants wilt. Pick fruit as soon as it starts to color if heavy rain is on the way.
Fight anthracnose by picking tomatoes before they get fully ripe on the vine. The fungus targets soft, ripe fruit most. Let them finish on your kitchen counter instead. Remove any fallen fruit from around plants since rotting tomatoes spread spores fast.
When I first saw blossom end rot, I bought calcium spray right away. It didn't help at all. What fixed the problem was setting up drip irrigation on a timer. My plants got water at the same time every day after that. The rot stopped showing up on new fruit within two weeks.
Not all damaged fruit is lost. Eat cracked tomatoes the day you pick them and cut around the split. Trim away blossom end rot if it hasn't spread deep. Only anthracnose needs to go in the trash since fungus spreads through flesh beyond what you can see on the surface.
Read the full article: 8 Common Problems With Tomato Plants and Solutions
