Too Much of a Good Thing: Fertilizer Burn in the High Tunnel
- Jul 23
- 5 min read
Gardening is full of lessons. Just about the moment you think you might have a few things figured out, something happens.
Sometimes weather happens, pests happen, disease happens, and other times it's us. We happen.
Fertilizer is one of those things where there is, in fact, too much of a good thing. Don't ask me how I know. I've burned plant starts with bottled blue stuff and mature plants with organic real stuff. This year it was the "NO BURN," well-composted chicken manure that got me. Nothing makes your heart sink like watching perfectly healthy plants suddenly get brown leaves and look on the verge of death. Ugh.
Signs of Fertilizer Burn — and How to Fix It
Signs to watch for: browning or crisping leaf edges, sudden wilting on otherwise healthy plants, and leaves that look scorched rather than yellowed.
What to do: water thoroughly and repeatedly, ventilate an enclosed space like a high tunnel, prune the damaged leaves after 2–3 days once things stabilize, and be patient — most plants bounce back.
Gardens (and Sourdough) Are Full of Lessons
Gardens take time, care, and attention. It isn't as complicated to grow things as the internet might have you think. Yet it's more full of lessons than you want it to be. It's a lot like sourdough bread. For something pretty straightforward that's been done for generations (cue, all the way back to Bible times, hence the feast of unleavened bread, because the people didn't have time to let their bread rise) the modern internet world we live in has managed to complicate it to the point that many people don't even try because it seems too hard. I digress.
Gardens and sourdough — you can do both, they're not complicated, but you'll learn some lessons along the way. I'd just say don't be intimidated. Every loaf won't be perfectly beautiful. You might kill a few plants. But the beautiful loaves and the vibrant, delicious, nourishing plants are worth it.
Back to burning plants. Maybe I can help you avoid my mistakes. God has a way of keeping me humble, and that's okay. I'm glad, actually. If I got it all right all the time I would undoubtedly be the most prideful person you ever met. So I'm thankful that the Lord disciplines and trains us, often through failure.
The Fertilizer That Got Me
Here's the stuff I used. It's great — really great. Our plants have loved it. I'll use it again. But I won't dump five bags of it all over our high tunnel mid-growing season. 🙃
Also, I should warn you: this stuff STINKS. It really stinks. You will stink, your car will stink, and your garden will stink — for a few days. But again, when you watch your plants, you might think the trade-off is worth it. I do. I've tried several natural fertilizers, and I can say chicken manure is the one I personally think performs best. I've used freshly cleaned-out chicken coop nastiness in lasagna beds, and now this neatly packaged, already-composted fertilizer.
Between natural fertilizers, steer manure, and fish fertilizer/salmon, I see the most noticeable difference from chicken manure.
While we aren't strictly organic gardeners (meaning we give our plants some "vitamins" in the form of Jack's fertilizers), I do believe in feeding the soil. A targeted, combined approach is what makes the plants look their best, in my limited home garden experience.
What Went Wrong in the High Tunnel
From now on, this will be an amendment I start the season with, but likely skip adding to mature plants. I also recommend letting it off-gas in a wheelbarrow. This last batch was wet, and I honestly think the ammonia buildup in our closed high tunnel is what did the most damage. Basil and cucumbers took the worst hit. Thankfully it only killed a couple of plants, but it sure gave several a stinging setback. Combine that with our flood-watch levels of rain, clouds, and cold, and our poor cucumbers are slow going.
The odd thing about a high tunnel is that it can pour rain and you still have to water. Something about that — pouring rain on the roof of the high tunnel — is very relaxing and also odd. I love it when God waters our outside gardens. I haven't quite gotten over trudging out in the rain to water plants under a cover. Still, the added degrees during a cold rainy spell in Alaska are what make high tunnels worth their hassle and cost. When the weather is horrible but you can still be "outside," protected from wind, rain, and the Alaska chill, that's such a gift. I had no idea how much I would enjoy just hanging out in the high tunnel. It's truly extended the summer feel from four months to six for me. Four months of summer feels lacking. When you can count on being outside and warm enough to enjoy it for half the year, what a blessing!
So If You Burn Your Plants, What's Next?
The good news: the majority of the burned plants are bouncing back. You watch your plants brown and worry that you did them in.
I watered thoroughly a few times. We opened the tunnel for a few days, even overnight, and let everything air out. The garden wasn't destroyed by fertilizer burn, but it sure looked like it might be. After about three days, once things seemed to pause getting worse, I pruned the bad stuff off. It took a few rounds to get everything cleaned up, but once the bad leaves were gone, only a few plants looked totally bare. I believe I only really lost two plants to this stunt.
We entered a round of serious rain on the tail end of this. Thankfully the Lord gave us one sunny, windy day that let everything dry out after the excessive watering. Now I have a few spots where the manure is molding — looking forward to the next patch of sun so the plants can finish producing. Our tomatoes need some heat and sunshine, as do all the other warmth- and sun-loving plants.
Keep Sowing Seeds
Make the mistakes, but keep sowing seeds! Gardening is a skill that’s worth learning, even if the easier route is a quick trip down to the grocery store. Knowing where to your food comes from, how to grow it, and how to rely on God to make it grow is worthy endeavor.
