How Long Do Potatoes Take To Grow

How long do potatoes take to grow? It’s safe to say that gardeners love to watch their crops grow. We wait patiently for each sprout to mature and produce perfectly ripe fruit or vegetables. 

But when it comes to root vegetables, we can’t just watch and wait. We have to time the harvest just right. Pull your produce too early, and you’re stuck with unripe, tiny veggies. Wait too long and you take a risk on the crop being overripe – or even beginning to rot underground.

So, just how long do potatoes take to grow? If you follow these simple guidelines, you’ll have no problems timing your harvest – and growing beautiful and tasty taters!

Consider your climate

The first thing you’ll need to consider is your local climate. Potatoes don’t like very warm weather. This means that you can begin planting as soon as the danger of frost has passed and you’re able to work the soil.

In more Northern regions, it can be a gamble to plant early potatoes earlier than March. But you can cover young shoots with plastic containers, burlap sheeting, or mulch overnight to protect them from late frosts.

Temperature

On the other hand, if you live in a very hot climate, you may need to plant earlier – like December or January. You may need to avoid the extreme heat of summer – it can wreak havoc on your crop. Closer to the Equator, potatoes are even grown as a winter crop and you may be planting in November or December.

Potato drills with good green healthy foliage
Potato drills with good green healthy foliage

It’s really all about the soil – we need both the right temperature and humidity levels. At planting the soil temperature should be at least 10°C (50°F). It should also be dry enough not to stick together – not only will clumpy soil be hard to plant in, but seed potatoes can rot if the ground is too wet.

Your potatoes will grow best in a sunny location with cool, loose, well-drained soil. The ideal temperature range is 16 to 20 degrees Celcius.

Rainfall

If your climate has low rainfall, you will most likely need to water your potato crop. Growing potatoes require at least an inch of rain a week to grow well.

Which variety of potato

Do all potato varieties take the same time to grow? More or less. Most potatoes can be harvested between 90 and 110 days after planting.

There are three main types of potato varieties and, while some are ready in just under 3 months, some take an extra month to mature. Early varieties or new potatoes will be harvested earlier in the year than maincrop. But maincrop varieties are bred to produce bigger potatoes with higher yields.

Chitting potato seed

If planting earlies, you should prepare your seed potatoes ahead of planting by “chitting” them. Find a frost-free place that gets lots of light. Stand your seed potatoes in an egg carton or seedling tray with the rose end (where you see the most eyes, or small dents) pointing up.

When the shoots are about 3 cm (1”) long, you can prepare them for planting. Remove the weakest shoots, leaving 4-6 per tuber. Next, section your seed potatoes into 1-2” chunks, leaving a shoot on every piece.

This method can also be useful for maincrops. You can begin the process indoors while there is still frost in the garden. This lets you get a jumpstart on the growing season. Have a look at these seed potatoes to see which you like the look of.

Growing potatoes in containers

Most of the earliest new potatoes are grown in warm climates, in sunny patches of gently sloping soil. If you don’t happen to live in the ideal early potato climate, you can still harvest new potatoes by mimicking their favorite growing conditions.

Try growing your potatoes in containers, greenhouses, or even polytunnels. This will warm the potting soil and increase the growth rate of your crop. Remember not to let the potting soil dry out, so be sure to water your potato plants regularly.

When the weather warms up enough to eliminate the risk of frost, you can also move the containers to a sunny spot outdoors. Just be sure that your containers don’t get too hot!

Early, mid or late season potatoes

Many believe that early-season potatoes are ready sooner than maincrop varieties but that is debatable.

Early varieties do not necessarily mean they are ready quicker – just that they are ready earlier in the year. The same goes for mid-season and maincrop. All potatoes take roughly the same amount of time to grow it’s just that their planting dates determine the time of year they are ready to harvest.

The exception to this is if the potatoes are baby potatoes or Salad varieties may be ready at 80 days as they are harvested at a smaller size

Earlies

Early potatoes planted in Mid Feb may only be ready by the  7th to 14th July which is around 112 days. It may be possible to harvest at 100 days in warmer climates or if they grow really well.

You can start harvesting them as soon as the first large tubers appear – these tender young spuds can be very tasty. Their thin skin means the potatoes need to eaten within a few days or they will spoil.

Midseason

Usually, mid-season potatoes are planted in mid-March and ready by August again around 120 days. A mid-season potato is deemed mid-season as this is the optimum time of year the variety has been bred to grow.

Maincrop

potato tops with the white flower bud getting ready to open
potato tops with the white flower bud getting ready to open

Maincrop or late season potatoes take between 100 to 120 days to grow and mature. They are usually the highest-yielding potato varieties and are designed to grow to full maturity and have thick skin for long-term storage.

Maincrop potatoes are designed to be mature later in the year so they are harvested in closer weather, enabling farmers to use the colder months to store them well.

Potato planting dates

Planting time varies, depending on your location and the type of potato you’re growing. In colder regions, you’ll want to plant slightly later, and in warmer climates, you can plant a little earlier. If growing in containers, then you can also plant anytime as you will be indoors.

As a general rule, early potatoes should be planted by March. Mid-season varieties are typically planted by April and maincrop late-season potatoes by May.

While healthy potato plants can tolerate light frosts or even a mild freeze, they can’t survive hard freezes. Potatoes should be planted in cool weather – after the danger of freezing is past, but well before hot weather sets in for the summer.

Still unsure? You can try a garden planning app to determine the best outdoor planting dates for your area.

Potato harvesting dates

A good rule of thumb is 100-120 days after planting. You can also watch your potato plants for signs that your crop is ready to harvest.

You can check for new potatoes a few weeks after the plants have finished flowering. With their thin skins, these baby potatoes won’t be cured or stored, so only pull enough for 2-3 days, and be sure to store them somewhere cool.

When the foliage begins to yellow and die back, your potatoes will be almost ready. You can stop watering your crop at this point, and when the plant tops have completely died, you can begin to harvest the potatoes.

Digging potatoes

Start by digging up a test hill to determine if your potatoes are mature enough to harvest. The skins of mature potatoes are thick and firmly attached to the flesh. If the skins are thin and rub off easily, your potatoes should be left in the ground for a few more days.

Remember that although potatoes can tolerate a light frost, you will need to dig them out before the first hard frost is expected. You shouldn’t wash newly dug potatoes – the freshly harvested tubers need time to cure and for the skins to dry before they can be stored.

You can cure your crop by arranging the potatoes to have good airflow through them and allowing them to sit at room temperature for about two weeks. Once cured, the potatoes can be stored in a cool, dark place for 6 months or more.

Factors affecting maturity

As mentioned earlier, chitting or pre-sprouting your potatoes will help cut the outdoor growing time by at least a couple of weeks.

Using fertilizer will also help your plants grow well and increase the yield. You should add a suitable potato fertilizer when planting your seed potatoes. If you feel they are lacking in size later in the year – say at flowering – you can add more if you feel they need it. The fertilizer can be homemade fertilizer or bought in.

The white flower fully opened on a potato plant
The white flower fully opened on a potato plant

The note about adding a good amount of fertilizer is that it can extend the growing season of the potato. So although your potatoes will be bigger, they can take longer to mature.

Controlling tuber size

Again there is a note to mention here that, when growing with optimum fertilizer rates, your potatoes may begin to get too big. You may need to stop the crop growing by spraying with a crop desiccant or cut them down to soil level.

Covering your young potatoes at planting can help them become established as well as protect them from late frosts. You can use plastic containers, mulch, or even an old blanket. Leaving your potatoes vulnerable to frost can definitely lengthen maturation times, and also puts them at risk of dying.

And remember, the soil in which your potatoes grow will be especially rich in nutrients, so you shouldn’t just let it stay vacant after the harvest. If you planted earlies, you may be able to sneak in a crop of beans, tomatoes or squash.

How long do potatoes take to grow

As we’ve seen, many things influence how long potatoes take to grow. Variables such as potato variety, climate, chitted seed, and amount of fertilizer all play a part. Taking all these things into account, the average length of the growing season for potatoes is between 90 to 120 days.

You can harvest baby potatoes in slightly less time; plan to start harvesting the soft and creamy young potatoes after just 80 days. These, like new early potatoes, need to be eaten within a few days.

By following these simple guidelines, you can get definitely get the most out of your potato plants this season. So, which seed potatoes will you choose this season?