Potatoes are a staple in many home gardens, offering a rewarding harvest for those willing to put in the effort. However, one crucial factor that many gardeners overlook is whether they are growing determinate or indeterminate potatoes. Understanding the difference between these two types can significantly impact your planting, care, and harvesting techniques.

Seek out Certified Seed Potatoes!

Whichever type of potato you wish to grow, first it is important to source certified seed potatoes from a local supplier as these are certified to be free of diseases like blight, wilt and other potato viruses. They are also selected for vigorous growth and high yield and you can be sure you are getting a variety of potato that not only suits your climate but will also produce a crop that will produce tubers of good size and taste. They are also stored properly to ensure good sprouting.

While it may be tempting to plant the supermarket potatoes sprouting in the back of your pantry, it is not advised as they may be treated with sprout inhibitors to stop them growing, or may carry diseases that can infect your soil, potentially ruining future crops. 

Choose Certified Seed Potatoes from Reputable Local Grower

What Are Determinate and Indeterminate Potatoes?

In Australia, there is unfortunately very little information available about potato varieties and whether they are determinate or indeterminate, largely because the commercial growers don't really care as they grow them all the same way - which is in large fields all harvested by machinery where potatoes are then screened and the best sent to market. However, different varieties of potatoes fall into two camps depending on which way they grow, above and below the ground.

Determinate Potatoes
Determinate potatoes grow to a set height and produce tubers in a single layer, close to the soil surface. The above ground growth, ie the leafy, green part grows to about 60cm tall. They tend to have a shorter growing season and are ideal for gardeners who want an early harvest. Some determinate potato varieties include Norland, and Avanti.

Determinate Potatoes Growing in Single Layer Below Soil Surface

Indeterminate Potatoes
Indeterminate potatoes, on the other hand, continue growing throughout the season and can develop multiple layers of tubers below the surface as the plant grows upward by using the hilling or mounding technique to encourage further tuber growth. These varieties take longer to mature but yield more potatoes per plant. Above ground growth can reach over 1 metre in height. Some popular indeterminate potato varieties include Mozart, Prince of Orange, Russet and White Star.

Indeterminate Potatoes Benefit from Vertical Growth To Produce Multiple Tuber Layers

How to Grow Determinate Potatoes:

Because determinate potatoes produce tubers in one layer, they require a bit more space. Here’s how to grow them successfully:

1. Choose a Suitable Growing Location – Select a well-draining site with full sun exposure.
2. Prepare the Soil – Loosen the soil to about 20cm deep and amend with mature compost, animal manures and biochar to help retain nutrients and moisture.
3. Plant the Seed Potatoes– Plant them about 10cm deep and about 25-30cm apart.
4. Water Consistently – Keep the soil moist but not waterlogged.
5. Mulch for Protection– Add a layer of straw mulch such as lupin, to retain moisture and prevent weeds.
6. Harvest Early – Most determinate potatoes are ready in about 70-90 days. Once the foliage turns yellow and dies back, carefully dig up the tubers.

How to Grow Indeterminate Potatoes:

Indeterminate potatoes require a different approach, as they continue growing upward. Here’s how to maximise your yield:

1.Select a Deep Container or use a Potato Grow Bag – Since indeterminate potatoes grow in layers, planting in deep beds, potato towers, or grow bags allows for vertical growth. Position your containers or grow bags in full sun.
2. Prepare the Soil – Use loose, well-aerated soil rich in organic matter. We recommend a 50:50 mix of mature compost and straw mulch. A handful of biochar is also recommended for nutrient and water retention.
3. Plant in Layers – Start by planting seed potatoes about 10cm deep. As the plants grow, continue adding a 50:50 mix of compost and mulch (a process called hilling) to encourage additional tuber formation.
4. Hill Up Regularly – Every few weeks, add more of your compost mix around the growing stems, leaving the top leaves exposed.
5. Maintain Moisture Levels – Water consistently to prevent the soil from drying out, as uneven watering can lead to malformed tubers.
6. Harvest Later – Indeterminate potatoes take between 120 - 180 days to mature, depending on variety and size. Once the foliage dies back, dig deep to uncover multiple layers of potatoes.

Planting Seed Potatoes in Grow Bags

A Few More Tips for your Best Ever Potato Crop

No matter which type of potatoes you choose to grow, all types will benefit from regular feeding during the growing season with a liquid fertiliser such as a fish emulsion which helps to drive growth. When watering potatoes, it is best to water in the morning to reduce incidences of fungal disease. Keep an eye out for any pest activity such as aphids, thrips or caterpillars so you can treat early. Planting companion flowers and herbs such as catnip, coriander, marigold and tansy will help encourage predatory insects to keep pest numbers in balance. Planting a companion crop of faba (broad) beanswill also help to provide a source of nitrogen to the soil for a more robust crop, without competing with potatoes for nutrients. 

Never plant potatoes in the same soil two seasons in a row. If you are planting in grow bags particularly, it is best to empty soil (put in your hot compost which should kill any lingering pathogens) and thoroughly clean your bags after harvest, and start with fresh soil for subsequent plantings. If you are growing in the ground, follow your potatoes with a legume crop and then a mustard crop to help naturally fumigate and remediate your soil.

Freshly Harvested Potatoes

Choosing the Right Potato for Your Table

So it goes without saying that you should grow what you like to eat - although, in my humble opinion, there is no such thing as a bad potato, and a homegrown one is next level, so if you have the space, I would be inclined to grow few different types to cover all bases! 

Different types of potatoes work best for different cooking methods based on their starch and moisture content. For mashed potatoes, you want a high starch content with low moisture and a fluffy texture that breaks down easily when cooked. Meanwhile, the best roast potatoes are made with a medium starch and slightly waxy interior to keep the inside soft and creamy but will still crisp nicely on the outside. Waxy, low starch varieties are best for your potato salads as they hold their shape well when cooked, while high starch and low moisture potatoes with a firm structure make for super crispy chips and fries that don't go soggy.

And the Winner Is.....

Drum roll please ........ You! The best potato you will ever eat is the one you grow yourself, no matter what the variety. But in summary, if you prefer an early harvest with minimal maintenance, determinate potatoes are your best bet. However, if you want a larger yield and are willing to invest time in hilling, indeterminate potatoes can be more rewarding by providing a larger yield over a longer period of time.

By understanding the growth habits of determinate and indeterminate potatoes, you can choose the best method for your garden and enjoy a bountiful harvest. Happy planting!

Check out these other great blogs all about growing and eating the humble spud.

Everything You Need to Know About Growing Potatoes

Plant Spotlight on Potatoes

VIDEO: The Fail-Safe Way To Grow Potatoes (Growing Potatoes In Bags)