πŸ’§ DIY Hydroponics with Scrap PVC: Growing Bok Choy the Easy Way (No Pump Needed!)

Ever looked at leftover construction material and thought, “I can grow food with that”? That’s exactly what happened when I got my hands on some scrap PVC pipes from a neighbor’s septic upgrade. Instead of tossing them, I turned them into a low-tech hydroponic system — no pump, no electricity, just gravity and nutrient water. And my first crop? Fast-growing, tender Bok Choy.

πŸ› ️ The Setup: Simpler Than You Think

I started with a 57-inch length of 5-inch-diameter PVC, gave it a quick rinse, and drilled evenly spaced holes about 2 inches apart along the top. Into each hole, I dropped a standard-sized clear plastic cup. These will hold my net pot substitutes — filled with a lightweight medium like coco coir or rockwool cubes.



The whole pipe sits on a raised container to keep it level and stable. No need for pumps, filters, or air stones — I’m using the Kratky method, which lets the water level drop over time as the plant consumes it, leaving an air gap for roots to breathe.

πŸ§ͺ Nutrients: Custom Mixed for Leafy Greens

The total internal volume of my pipe — filled ¾ of the way — holds about 13.75 liters of water. That’s the sweet spot for a Kratky-style fill: deep enough for roots to soak, but with headroom for air as the level drops.

For nutrients, I used the tried-and-true trio:

  • 4-18-38 (Masterblend or equivalent)

  • Calcium Nitrate [Ca(NO₃)₂]

  • Magnesium Sulfate (Epsom salt)

Here’s what I mixed into the 13.75 liters:

  • 22 grams 4-18-38

  • 22 grams Calcium Nitrate

  • 11 grams Magnesium Sulfate

Or if you're eyeballing it with kitchen tools:

  • ~3.5 teaspoons 4-18-38

  • ~3.5 teaspoons Calcium Nitrate

  • ~1.75 teaspoons Magnesium Sulfate

πŸ’‘ Pro tip: Dissolve each powder separately before combining in the final mix. Always use non-chlorinated water and adjust your pH to around 5.8–6.2 for Bok Choy.

πŸ₯¬ Why Bok Choy?

Bok Choy (also known as Pak Choi) is perfect for beginners. It grows fast, doesn’t need a ton of space, and thrives in Kratky systems. The seed pack I used is labeled in Chinese, but Bok Choy is pretty forgiving as long as you give it a steady supply of nutrients and light.

Within days of planting, I expect to see germination, and harvest usually comes in 30–45 days depending on variety and conditions.

🌱 The Microsteader’s Takeaway

You don’t need to spend a fortune on hydroponic gear. With a leftover pipe, some plastic cups, and a few cheap powders, you can grow real food on a balcony, patio, or sunny corner — no soil, no mess.

This project cost me next to nothing but will produce fresh, nutritious greens for weeks. That’s the power of microsteading: low input, high return. And best of all? It’s scalable. Add another pipe. Try a different crop. Experiment.

Because sometimes, the best systems start with scrap.

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