Today we’re talking about kale, that “superfood” everyone wants in their smoothies and salads. But this grow log is special: unlike the basil grow we covered earlier — which went smoothly from start to finish — here we made a common mistake: underfeeding.
We’re sharing it so you lose your fear of nutrients. Kale is a voracious plant, and if you don’t feed it enough, it lets you know. Let’s look at how we spotted the problem and how the plants exploded once we corrected their diet.
Seeding
Día 0 — 5 de abril | EC 150 ppm | pH 5,5
We started as always: seeds in the sponges, plastic domes on, and maximum moisture.
At 150 ppm we’re using base water only — at this stage the seed has its own nutrient reserves and doesn’t need anything more.
Germination
Day 6 — April 11 | EC 150 ppm | pH 5.7
The sprouts are here. They look healthy, but we made a conservative call: we kept EC at 150 ppm.
The mistake: When we saw the first green, we should have started gently raising the dose (to around 300 ppm). By not doing so, the plants began burning through their internal reserves too quickly.
Slow growth
Day 11 — April 16 | EC 250 ppm | pH 6.0
Five days later and the plants are growing, but slowly. We nudged EC up to 250 ppm.
Visual diagnosis: Compared to basil at the same point in the grow, the kale is much smaller. The leaves look pale. The plant is surviving, not thriving.
The warning sign
Day 22 — April 27 | EC 350 ppm | pH 5.8
Nearly a month in and the plants have true leaves, but they look “thin” and sparse. The diagnosis was clear: they’re hungry.
An EC of 350 ppm for a month-old kale plant is very low. This plant needs a lot of nitrogen to build large, dark leaves. We were being too cautious about burning the roots, and ended up stunting the development instead.
The turning point
Day 26 — May 1 | EC 500 ppm | pH 5.5
Time to act: we raised the dose to 500 ppm and adjusted pH to 5.5 to maximize nutrient absorption.
The plants begin to stretch, reaching to take in that new energy entering through the roots. The change in structure is already visible.
The explosion
Day 33 — May 8 | EC 700 ppm | pH 5.7
Boom! The difference in just one week after correcting the feeding is striking. After moving up to 700 ppm, the plants responded powerfully: the leaves widened and the green deepened to that rich, intense color that’s the hallmark of healthy kale.
Lesson learned: Hydroponics is fast. If you correct a mistake in time, plants have a remarkable ability to bounce back.
Harvest
Day 39 — May 14 | EC 700 ppm | pH 5.5
Under 40 days and we already have a harvest-ready crop. The leaves are large, textured, and crisp. Despite the slow start from underfeeding, the final result was excellent. We held EC at 700 ppm all the way through.
Takeaways
This grow log leaves us with three key lessons:
- Don’t be afraid of nutrients: Especially with leafy greens like kale or Swiss chard. They’re heavy feeders that need to be fed accordingly.
- Learn to read your plant: If growth stalls in week 2 or 3 and the leaves look pale, check your EC meter — you’re probably coming up short.
- Recovery is possible: As the May photos show, going from 350 ppm to 700 ppm saved the crop and practically doubled plant size in 10 days.
Has underfeeding ever happened to you? Tell us in the comments!