How to grow potatoes in hot climate

Leimone Waite
Master gardeners

Q: Can you provide some advice on how to grow potatoes? I planted some this spring but they are already looking very sad and have not flowered yet.

A. Potatoes can be a bit tricky here in North State heat.

Potato plants can't withstand hard frost and plants wither and die once temperatures are consistently over 100 degrees. Additionally, potato plants fail to set many tubers when nighttime temperatures remain over 55 degree. Most potato varieties need 80 to 110-degree days for them to develop full size potatoes and we don’t get that many days in the spring between freezing and scorching hot in the valley.

You may have the best luck growing "new potatoes." These are potatoes harvested young so that they are small and have thin, tender skins.

Choose seed potatoes from a local nursery or garden catalog. Look for varieties with shorter days to harvest. Red potatoes are a good choice for new potatoes, but you can also choose white, yellow or blue.

You can grow potatoes from spuds purchased from the grocery store, but many of these potatoes are treated with Chlorpropham — a herbicide and growth inhibitor — to inhibit sprouting, and they can also carry potato diseases. Organic potatoes are not treated with a sprout inhibitor but you still run the risk of bringing disease into your garden. Many of these diseases will infect any plant within the same family such as tomatoes and peppers.

North State gardeners have reported success growing potatoes in grow bags. With this method they start potatoes in grow bags in the garage or other protected area in late February or early March.

To plant in grow bags, set seed potatoes out in soil in the bottom third of a bag that’s been enhanced with organic matter and fertilized with a balanced fertilizer. An easy method is simply to place the potatoes cut side down — make sure the cut has dried out — on top of the soil, and cover them with straw or compost. As the sprouts appear, continue to add straw, loose soil or compost. Move grow bags out into the sun during the day and bring them into a protected area at night until danger of frost has passed. As the plants grow, continue to add loose soil, compost or straw, leaving several sets of leaves exposed. Potatoes grow from the stem so you want to add the straw or other loose soil and compost up the stem until the grow bag is filled. If gophers or ground squirrels are pests where you live, this method also works well to keep them from eating all your potatoes.

Once the potato plants have blossomed you can start feeling around for early potatoes to harvest. Some potatoes can be harvested without harming the plant.

Make sure to keep potato tubers well covered as too much sun exposure causes greening, indicating the presence of a toxin called solanine. Green potatoes should not be eaten.

When the tops have wilted and dried up, you can harvest your entire crop.

The Shasta Master Gardeners Program can be reached by phone at 530-242-2219 or email The gardener office is staffed by volunteers trained by the University of California to answer gardeners' questions using information based on scientific research.