You should always leave 6 inches of the stem showing. You can add dirt as they continue to grow.

Right now there is 6" of stem showing but there are also leaves on the stem. So, if someone could answer my question I'd appreciate it. Do I cover the leaves too?

lovetogarden,

Pull off the bottom leaves if you wish. If this is too much work, then yes, just cover with soil, straw, mulch, compost, etc. Hilling doesn't have so much to do with the stem or leaves as much as the tubers themselves. Hilling won't necessarily encourage potatoes to form all along the stem the higher you go. The goal of hilling is to provide a protected enough environment in order for the actual potatoes/tubers to form without turning green and developing solanine, a bitter and toxic (in significant quantities). Hilling improves drainage, minimizes tuber greening, minimizes frost damage, aids in weed control and facilitates harvesting. If you did not hill, the potatoes forming near the surface would turn green and the stolons near the surface which form the tubers may turn into foliage instead of tubers.

First you plant the potatoes in a trench below soil level, then as they grow, you keep adding more soil until you are hilling them.

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If you want to hill for potato production along the stem, you need to, hill often so that only two inches of stem are seen at the top.

What results in a higher yield is not so much potatoes along the length of the stem as much as proper growing medium with plenty of water retention as well as with plenty of drainage. Many gardeners hill, but their yield isn't optimum because their growing medium isn't optimum to begin with. If your growing medium is optimum you'll get a higher yield from plants that aren't hilled much vs. plants that are hilled to 8 feet in poor growing medium.

Thanks Violet. Great informative pics. I think I have the perfect soil, slightly sandy yet holds together in a clump when I squeeze it. Looks like I'll have to catch up on the hilling. Thanks again for the pics.

My pleasure. Let us know how it goes!

When do I start hilling my potatoes??