How to Grow a Massive Potato Harvest

How to Grow a Massive Potato Harvest in a Plant Box – The “Hill-As-You-Go” Method

If you’ve ever wanted to grow dozens of kilograms of potatoes in a tiny space, this simple trick will change everything. Instead of planting potatoes in the ground and hoping for the best, use a deep planting box and keep adding soil as the plants grow. This technique (often called “hilling” or continuous earthing-up) forces the potato plant to produce new layers of tubers all the way up the stem, dramatically increasing your yield.

At Plantboxes.co.za, we designed our modular planting boxes with exactly this method in mind. The textured pyramid sides not only look great, but they also give roots something to grip, while the deep design (up to 45 cm when fully stacked or more if needed) gives you all the room you need for layer after layer of potatoes.

Why This Method Works So Well

Potato plants form tubers on underground stems (stolon’s). Any part of the stem that is covered with soil can produce potatoes. Normally, when you plant in open ground, only the bottom 20–30 cm of stem is buried, so that’s all the potatoes you get. By gradually burying more and more of the stem inside a tall box, you can turn 45 cm of stem into potato-producing real estate – often tripling or quadrupling your harvest from the same number of seed potatoes.

What You’ll Need

• Deep modular planting box from Plantboxes.co.za (one box is perfect for a beginner; two or three stacked give insane yields)
• 1 certified seed potato (choose a high-yielding variety such as BP1, Up-to-Date, Mondeo, or Valor)
• Good-quality potting soil or compost-rich growing medium
• Organic fertiliser or well-rotted manure

Step-by-Step Guide

1. Assemble your Plantboxes.co.za box. Start with the base unit and one or two extension sides (the more sides you eventually use, the bigger the harvest).
2. First planting (early spring) Fill the box only 15cm deep with soil. Place 1 seed potato evenly on the soil, sprouts facing up. Water well.
3. Let them grow. When the shoots are 15–20 cm above the soil, it’s time for the magic.
4. Add the next layer. Gently add another 15cm of soil, burying all but the top few leaves. If you’re using modular Plantboxes, simply click the next side on and fill it.
5. Repeat, repeat. Every time the plant grows another 15–20 cm above the soil, bury the stem again. Keep adding sides and soil until the box is full or the plant starts to flower heavily (usually 3–5 layers total).
6. Water and feed. Potatoes love consistent moisture but hate waterlogging – our boxes have excellent drainage. Feed every 2–3 weeks with a potassium-rich organic fertiliser (potatoes are greedy feeders).
7. Harvest time: When the leaves start yellowing and dying back (normally 12–16 weeks after planting), simply tip the box out or remove sides one by one. You’ll find beautiful, clean potatoes all the way from the bottom to the top layer – no digging required!

Real-World Yields

From a single 45cm deep Plantboxes.co.za stack and just 1 seed potatoes, growers regularly harvest more than triple their normal harvest

That’s the kind of yield that used to need half a backyard – now possible on a sunny patio or balcony.

Ready to grow your own mountain of potatoes? Visit Plantboxes.co.za today and grab the exact deep modular boxes that make this technique so easy and effective.

Happy planting – and even happier eating! 🥔