Growing potatoes is easy, but getting a good yield of decent sized potatoes is not. By the time your potatoes reach harvest, you will have invested your materials, time and labour, so do not leave soil conditions to chance. The temperature of the soil, drainage, PH and nutrients all play a role in the outcome of your crop. Plan now, and reap the rewards of a bountiful potato harvest.
Plant your seed potatoes (sprouted tubers) after the risk of frost. The lower the soil temperature is at planting time the longer it will take for your potato plants to break through the ground. Early tuber development needs a consistent soil temperature of at least 12.8 degrees Cor five to seven days to avoid brown centre, a condition that can lead to a hollow heart in the potato, according to Mike Thornton and Phil Nolte at the University of Idaho Agricultural and Life Sciences Research and Extension. Planting seed potatoes that are at least two ounces and no deeper than recommended will help protect the potatoes from frost. Once foliage appears, protect your potato vines from frost with a row cover or straw. Remove the protection from the plants on sunny days.
B Rosie Lerner, Extension Consumer Horticulturist at Purdue University, recommends working two to three pounds (for every 100 square feet) of balanced fertiliser with a 12-12-12 ratio into your potato bed. She also recommends working in a moderate amount of organic material at this time.
Potatoes prefer a soil that has good drainage. Planting seed potatoes in wet soil causes compaction, which damages the soils ability to drain properly and hold nutrients. This can cause disease and rotting of the seed potatoes. Potatoes have shallow roots and can become stressed if watered excessively. Mainpotatolady.com suggests watering uniformly during the growing season, but cease watering two weeks to a month before harvest. Soil that is too dry leads to slow-growing yellow plants. Finding the perfect balance for watering potatoes can be a challenge, but is important for yield and potato size.
PH Value of Soil
A soil PH value defines how acidic or alkaline your soil is. A PH test kit can be purchased at most garden centres and some hardware stores. The soil PH value preference for potatoes is 5.3 to 6.0, which is slightly acidic. While potatoes will still grow outside this range, there are ways to adjust the PH of your soil. The addition of lime or wood ash to your potato bed will raise the PH of the soil, while adding aluminium sulphate or sulphur will lower the PH. For the most benefit from your soil additives, test the PH of your soil and prepare the garden bed in the fall before planting. Be aware that raising the soil PH level too high can lead to scab, a serious potato disease. Selecting a scab-resistant potato variety is an option.