How to Grow Tomatoes Organically (Without Losing Your Mind)

Freshly picked tomatoes from a garden in Rideau Lakes

Planting Deep, Composting Right, and Tackling the Weird Stuff That Comes Up

Growing organic tomatoes is one of those things that make you feel like a rockstar gardener… or like you’re in way over your head. There’s not much in between. But if you get the basics right—especially when it comes to soil health, consistent care, and understanding what the plant actually needs—you can grow big, bold, beautiful tomatoes, even without a single drop of synthetic fertilizer.

Plant Tomatoes Deep (Trust Me)

Tomatoes don’t want to be perched daintily at the top of the soil. They want to be buried deep. Strip off the lower leaves and plant them right up to their first true leaves. That whole buried stem will shoot out roots, making for a stronger plant that can reach water and nutrients more easily.

You can even trench them sideways if you want the roots to hit warmer soil layers earlier in the season. Either way, don’t baby them by planting them shallow—it makes a world of difference.

Compost Is Queen

Plants eat dead plants 🪴 What are you feeding yours?

I always tell people: give your garden a good three-inch layer of compost every year. This one step alone will have your soil singing. A heavy annual application like that means you’re set for the season—your tomatoes will appreciate it more than you know.

If you’re doing succession planting or popping in new crops throughout the season, you’re going to need to top up a little more regularly. A tiny handful here and there might carry you to the end of July, but by August, your plants are hungry. I know this because in my containers, I use six large handfuls of organic fertilizer and even still, by mid-August, my tomatoes are starting to show signs of nutrient stress. That tells me two and a half months is about all you get from that amount—so plan to replenish.

A Few Foliar Tricks

Yes, plants can absorb through their leaves 🍃

Sometimes tomatoes need a little leaf-level love. Here are two sprays I swear by:

Milk Spray – Half milk, half water. Spray it right on the leaves to fight powdery mildew and give a boost of calcium. It’s simple, effective, and already in your fridge.

Whey Spray – If you can get your hands on whey (leftover from yogurt or cheese-making), mix it 50/50 with water and mist your plants. It’s like a probiotic for their leaves—nutritious and protective.

Morning is the best time to foliar spray. Let the leaves dry out through the day so you’re not encouraging mildew while trying to fight it.

The Five Most Common Tomato Problems (and How to Handle Them Like a Pro)

1. Blossom-End Rot

Prevent Blossom End Rot on tomatoes.

Black sunken spots on the bottom of the fruit? Classic. It’s often caused by inconsistent watering, not necessarily low calcium. Keep your soil evenly moist, mulch heavily, and toss some crushed eggshells or oyster shell flour around the base if it keeps coming back.

2. Blight (Early or Late)

Late Blight

If your leaves are getting ugly and spotty, you might be dealing with fungal blight. Clean up infected leaves, avoid overhead watering, and always rotate your crops. And don’t cram your tomatoes too close together—they need to breathe.

3. Tomato Cracking

Consistent watering to help fight tomato cracking.

When you let your plant get really thirsty and then drench it, the fruit swells too fast and cracks. Mulch helps prevent this. So does watering like you mean it—deep and consistent.

4. Hornworms

Tomato Hornworm (Manduca quinquemaculata)

These are stunning. Lime green, beautifully striped, and honestly kind of mesmerizing. I’m in awe every time I see one. That said, they will chew through your tomato plants like there’s no tomorrow. Hand-pick them and let the birds enjoy the treat. Or if you’re more hands-off, neem oil and beneficial insects like parasitic wasps can help manage them naturally.

5. Leaf Curl and Yellowing

Tomato leaf curl, another issue seen on our loved plants.

This could be water stress, pests, or just your tomatoes being dramatic. Trim off the worst leaves, check for aphids or whiteflies under the foliage, and give your plant a little foliar feed to boost its immune system.

A Quick Rant About Red Mulch

Okay. Let’s talk about red mulch.

You see it in big box stores and people think it’s fancy, but here’s the deal: don’t use it in your garden beds. It’s dyed. The dye fades fast, can leach out, and stain your walkways. It’s made from shredded wood, which actually robs nitrogen from your soil as it breaks down. And it’s so light that a good rainstorm will send it halfway across your yard.

Worst of all? That red colour is loud. Colour psychology tells us red is the strongest visual cue for the human eye. So guess what you’ll be looking at first in your garden? The mulch. Not your plants.

At first glance, you will only see the red mulch. Its our brains trying to keep us safe.

That being said… use red mulch under your tomatoes. Seriously. It reflects red light back up to the plant, which boosts fruit production. So yes, red mulch is useful—but only in that one specific spot.

Final Thoughts

Tomatoes are finicky, beautiful, and totally worth the effort. If you feed the soil with good compost, keep things consistent, and watch for the usual hiccups, you’ll be swimming in tomatoes come August. And if not, you’ll at least have learned a lot—and that’s half the fun of gardening.

Need help getting your garden off the ground, or looking to design something that actually fits your life and growing goals? Reach out. At Fine Lines, we connect people with nature in ways that go beyond the ordinary—and your tomato patch is a great place to start.