The Top 7 Problems with Growing Potatoes in Bags and How to Avoid Them

Growing potatoes in bags has become an increasingly popular method for home gardeners in recent years, The confined space of a grow bag allows for potatoes to be grown in small yards or even on patios Bags also make harvesting tubers clean and easy

But growing potatoes in containers has its own problems that you don’t have to deal with when you grow them in open garden soil. In particular, potatoes grown in bags don’t always do well and don’t produce a lot of good crops.

Gardeners have learned from their mistakes what the most common mistakes are when they try to grow potatoes in containers. By knowing about these possible issues, steps can be taken to avoid setbacks and make sure the bagged potato crop is a success.

1. Overheating

Overheating is one of the biggest problems with growing strong potatoes in bags. Dark-colored grow bags that are left out in the sun can get very hot. This extra heat stresses the potato plants and stops the tubers from swelling.

Research shows potato roots cease production of tubers when soil exceeds 75°F. The confined soil mass in containers heats up rapidly in the sunshine. Overheating is less of an issue when potatoes can spread roots deeply and widely in garden beds.

To prevent overheating:

• Paint or cover black bags and containers with reflective white or light colors.

• Move bags to partly shaded areas protected from intense midday/afternoon sun.

• Cover bag tops with insulating layers of straw mulch to maintain cooler soil temperatures.

• Ensure adequate and consistent soil moisture, as drought stress worsens heat damage.

2. Poor Drainage

Closely related to overheating is poor drainage. Since there is no way for water to escape, it can pool in potato bags and make them soggy. Excess moisture leads to tuber rot and promotes fungal diseases. Plants struggle with stunted growth in waterlogged soil.

Even fabrics like burlap designed for excellent airflow can become waterlogged in bags. Potting mixes also easily become compacted over time, reducing drainage.

To improve drainage:

• Use containers with sufficient drainage holes, adding more holes if necessary.

• Incorporate sand, small gravel, or perlite into potting mix to loosen texture.

• Avoid overwatering; allow soil to partially dry out between waterings.

• Place bags under cover during heavy rains to limit excess moisture.

3. Nutrient Deficiencies

The finite soil volume in potato bags cannot supply nutrients to satisfy plants for the entire growing season. Deficiencies quickly develop, evidenced by yellowed leaves and poor plant vigor. Low nutrients ultimately translate to dismal yields.

Frequent watering also washes away nutrients. Tubers are nutrient sinks, rapidly depleting soil reserves. Replenishment is needed to maintain productivity in containers.

To provide ample nutrition:

• Use potting mix enriched with organic fertilizer and quality compost.

• Apply a balanced liquid fertilizer, fish emulsion or compost tea every 2-3 weeks.

• Top dress bags with compost, manure or granular organic fertilizer midseason.

• Mix a slow-release organic fertilizer into soil prior to planting.

4. Uneven Soil Moisture

Maintaining evenly moist soil throughout entire bags can be tricky. Dry pockets within the container prevent tuber development on portions of plants. Erratic moisture also causes knobby, misshapen potatoes.

As plants grow, it becomes harder to water the middle and bottom of bags. The top of containers tend to get saturated while lower areas stay dry.

For consistent bag moisture:

• Use soaker hoses coiled around bags to give plants a steady drink.

• Insert moisture probes into bags and water when the bottom becomes dry.

• Periodically dump out bags and thoroughly soak the entire soil mass.

5. Overcrowding

When space is limited, it’s tempting to cram as many seed potatoes into a single grow bag as possible. But overcrowding leads to excessive competition between plants for water, nutrients, light and space.

Congested containers cause potatoes to bolt or get spindly as they reach for sun. Plants also bulge out awkwardly from overstuffed bags. Yields ultimately suffer from overcrowding stress.

To avoid overcrowding:

• Follow seed spacing guidelines, allowing each plant sufficient room to spread.

• Use larger containers or limit number of seeds according to bag size.

• After sprouts emerge, snip off all but the shortest, stockiest stem on each potato.

6. Unsuitable Growing Medium

The growing medium used inside potato bags is just as important as the bag itself. Regular field soil becomes compacted when used in containers, reducing drainage. Dense clay soils also accumulate moisture and heat up rapidly.

The ideal potting mix for potatoes is loose, lightweight and fast-draining, while still having good water retention. The perfect blend promotes lush foliage and large tubers.

Ideal potting mixes contain:

• Compost for moisture retention and nutrients

• Coarse sand or perlite for drainage and aeration

• Peat or coco coir to prevent compaction and add organic matter

7. Insufficient Winter Protection

The porous, breathable fabrics of most potato bags make them unsuitable for growing potatoes in cold climates. Bags provide little insulation against freezing autumn temperatures.

Exposure to cold causes tubers to convert starch reserves into sugar. This results in undesirably sweet-tasting potatoes. Hard frosts can damage plants and kill tubers.

In cool regions, bags need winter protection:

• Move bags to an unheated garage, shed or basement before heavy frosts arrive.

• Wrap or cover bags with layers of straw or bubble wrap to insulate the soil.

• Limit tuber exposure to light during storage to prevent greening.

When the unique needs of potatoes are properly addressed, grow bags can produce abundant container crops. Avoid pitfalls like overheating and poor drainage by selecting light-colored bags suited to container gardening and creating an adequately aerated, nutrient-rich growing medium. With extra diligence, your bagged potato harvest can thrive!