Growing potatoes in Illinois can be rewarding and fun. Potatoes are a hardy crop that can endure cold temperatures and are relatively easy to grow. Potatoes require a light, well-drained soil in a sunny location. If you are growing potatoes in Illinois, you will want to plant them in late April or early May in an area that has been amended with compost or other organic matter.
Be sure to keep the soil evenly moist and free of weeds. When the potatoes are ready to harvest, typically in mid-August to late September, you can dig them up and enjoy your delicious homegrown potatoes.
Illinois’s Hardiness Zones And Climate
Zone 5a is the coldest of the three zones, covering the northernmost and westernmost areas of the state. It has hot summers and cold winters, with average temperatures in summer ranging from the mid-70s to the mid-80s. Winters are cold, with temperatures averaging in the low 20s. This zone gets an average of 30 inches of precipitation per year, including light snowfall in the winter.
Zone 6a covers central and southern Illinois, and has a milder climate than zone 5a. Summers are hot and humid, with temperatures ranging from the upper 70s to the upper 80s. Winters are mild, with temperatures ranging from the mid-teens to the mid-30s. This zone receives an average of 35 inches of precipitation per year, including moderate amounts of snowfall in the winter.
Zone 7a covers the southernmost areas of the state, and has the mildest climate of the three zones. Summers are very hot and humid, with temperatures ranging from the upper 80s to the upper 90s. Winters are mild, with temperatures ranging from the mid-30s to the low 50s. This zone receives an average of 45 inches of precipitation per year, including moderate amounts of snowfall in the winter.
Illinois’ growing zones 5a through 7a provide a variety of climates suitable for a wide range of plants. From the cold winters of zone 5a to the hot summers of zone 7a, Illinois’ growing zones provide the perfect environment for any gardener’s needs.
Different varieties of seed potatoes
When selecting seed potatoes for growing in Illinois, it is important to be mindful of the variety’s days to harvest and the length of time you have before you want to harvest them.
Early-season varieties such as ‘Yukon Gold’ and ‘Red Norland’ have fewer days to harvest and should be planted as soon as possible for harvesting in late summer.
Mid-season varieties such as ‘Russet Burbank’ and ‘Kennebec’ have more days to harvest and should be planted in late April or early May for harvesting in fall.
Late-season varieties such as ‘Cara Russet’ and ‘All Blue’ have the most days to harvest and should be planted in late April or early May for harvesting in early winter. Be sure to select varieties with the right number of days to harvest for your intended harvest date. Some good potato varieties for Illinois include:
- Russet Potatoes: 85-95 days
- Yukon Gold Potatoes: 90-110 days
- Red Potatoes: 80-90 days
- Purple Potatoes: 90-110 days
- Fingerling Potatoes: 90-120 days
- Sweet Potatoes: 90-120 days
- White Potatoes: 90-100 days
- All-Blue Potatoes: 95-105 days
- Yellow Finn Potatoes: 85-95 days
- Kennebec Potatoes: 85-95 days
When To Plant Potatoes In Illinois
In Illinois, potatoes should typically be planted in late April to mid-May. This allows the potatoes to take advantage of the cool temperatures and moist spring soils in the state. Planting later than this can lead to reduced yields as the season progresses. The ideal planting dates for potatoes in Illinois are:
- Zone 5: Around April 15th
- Zone 6: Around April 7th
- Zone 7: Around March 24th
How To Plant Potatoes In Illinois
Begin the planting process for seed potatoes by tilling the soil to a depth of 8 inches and incorporating organic compost. Once you have done this, find a sunny location that receives at least 8 hours of direct sunlight and place the seed potatoes.
Plant the seed potatoes with the “eyes” facing upward, leaving a distance of 8 to 10 inches in between each. Cover the seed potatoes with a layer of soil that is 3-4 inches thick, and make sure to water them adequately. As the potatoes start to sprout, add more soil to the rows to keep them adequately buried.
Water the potatoes on a regular basis and remove any weeds from the area. For those living in hot and dry climates, you may want to cover the soil around the potatoes with straw, although this is not essential.
Caring For Potato Plants
Caring for potato plants is pretty easy – they’re incredibly hardy and generally no-fuss. Potato plants need full sun and well-drained soil to thrive. They should be watered deeply and regularly, allowing the soil to dry out between waterings.
Fertilizing is also important for optimal growth. Potato plants need a balanced fertilizer with equal parts nitrogen, phosphorus, and potassium. This should be applied every four to six weeks, depending on the soil’s nutrient content.
It is also important to keep the soil evenly moist, as potatoes do not tolerate dry or waterlogged conditions. Mulching around the potato plants can help retain moisture and reduce weeds.
When To Harvest Potatoes In Illinois
There are two sure ways to know your potatoes are about ready to harvest! The first is counting backward from your current date to their planting date. Potato varieties have an approximate number of days to harvest, so consult the days to harvest for the particular variety of potatoes you’ve planted. If you aren’t sure, assume it’s around 100 days.
The appearance of your potato plants is another dead giveaway. You will know your potatoes are ready to harvest when the foliage begins to turn yellow and die back. Your plants will go through an entire flowering cycle, which is nice because the flowers are really beautiful.
Allow the soil around the plants to dry before harvesting, but don’t allow it to be dry for too long. Once harvested, inspect the potatoes carefully- they should be firm and free of green or soft spots.
Carefully dig up the potatoes with a garden fork, taking care not to damage the potatoes in the process. Once the potatoes have all been dug up, brush off any excess soil and inspect them for any damage. Discard any potatoes that are damaged, as these are not suitable for long-term storage.
Finally, gently place the potatoes in a cool, dry, and dark area for storage. It is important to only store undamaged potatoes, as damaged potatoes can quickly rot.
