Planting Potatoes in July: Is It Possible?
Yes, you absolutely can plant potatoes in July, especially if you live in regions with a longer growing season or are looking to secure a second harvest. While the traditional planting window for maincrop varieties is typically from March to May, late planting in July opens up possibilities for a yield later in the autumn. The key to successful July planting lies in choosing specific types of seed potatoes that mature more rapidly and are suited to cooler, shorter days. This approach allows you to leverage the remaining warmth and daylight of late summer and early autumn for growth.
- Late planting in July is possible for a secondary harvest.
- Focus on early or second early seed potato varieties.
- Success depends on climate and variety selection.
- Consider alternative growing methods like pots.
The primary consideration for planting potatoes in July is the variety of seed potato you select. Maincrop potatoes require a long growing season, often 120-130 days, making them unsuitable for a July planting unless you are in the most southerly, warmest parts of the UK and planting very early in the month. Instead, your focus should be on 'early' or 'second early' varieties. These types are bred for quicker maturity, often requiring 60-100 days from planting to harvest. By selecting these, you significantly increase the chances of your potato plants successfully developing tubers before the first hard frosts arrive.
Furthermore, your local climate plays a crucial role. While southern England might comfortably accommodate a July planting, areas further north or with a higher likelihood of early autumn frosts may find it more challenging. It’s always wise to check local weather patterns and consult with local gardening experts or experienced neighbours to gauge the feasibility for your specific location. The goal is to give the plants enough time to produce a worthwhile crop before winter sets in.
Choosing the Right Seed Potatoes for Late Planting
When aiming to plant potatoes in July, the selection of seed potatoes is paramount. Maincrop varieties, which are harvested in late summer and autumn after a long growing period, are generally not viable for a July planting. They simply require too much time to develop substantial tubers. Instead, you should prioritise 'first early' and 'second early' varieties. These are often referred to as 'new' potatoes when harvested young, but they also represent your best chance for a decent yield when planted late.
First earlies typically mature in around 60-70 days, while second earlies take slightly longer, around 90-100 days. This shorter maturation period is what makes them suitable for a July planting. Varieties such as 'Swift', 'Lady Christl', or 'Charlotte' are often good choices for first earlies, while 'Nicola' or 'Wilja' can be excellent second earlies. It is worth checking the specific days-to-maturity listed for any seed potato variety you are considering. Some specialised varieties are even marketed for their ability to grow quickly, making them ideal candidates for extending the growing season.
It is also worth noting that seed potatoes purchased later in the season might require pre-sprouting or 'chitting' more vigorously than those planted earlier. Ensure your seed potatoes are healthy and have developed short, sturdy sprouts before planting. This gives them a head start, which is crucial when planting later in the year.
Alternative Methods for Growing Potatoes in July
When planting potatoes in July, especially if you are concerned about soil conditions or the length of the remaining growing season, alternative growing methods can be highly beneficial. Traditional trench planting might not be ideal if you want to maximise early growth or if your garden soil is already committed to other crops. Growing potatoes in pots or large containers offers greater control over the environment and can speed up the process.
Growing Potatoes in Pots and Bags
Using large pots, grow bags, or even sturdy sacks allows you to place your potato plants in the sunniest available spot, maximising light absorption. This is particularly useful for a late planting, as you can potentially move containers to follow the sun or bring them under cover if an unexpected early frost threatens. Start by filling your container with a layer of compost, then place your chitted seed potatoes on top, spacing them according to the container size. Cover with a few inches of compost. As the potato plants grow, you will need to 'earth up' – adding more compost around the stems. This encourages more tubers to form and protects them from light, which can turn them green and toxic.
For containers, start with a good quality, well-draining potting compost. Adding a slow-release fertiliser at the start can provide consistent nutrients for the entire growing period.
This method is also excellent for managing pests and diseases, as the plants are more isolated. When it comes to harvesting, you can simply tip the container out or carefully dig through the compost to find your new potatoes. For potatoes planted in July, this method can be particularly effective as it offers flexibility and a potentially quicker route to harvest compared to in-ground planting in cooler soils.
Using Growing Bags for Potatoes
Growing bags specifically designed for potatoes are an excellent option for a July planting. These bags typically have a flap at the bottom for easy harvesting and are made from durable material, offering good insulation. The principle is the same as with pots: start with a layer of compost, add your seed potatoes, and gradually earth up as the plants grow. The confined space also means you need to be diligent with watering, ensuring the compost remains consistently moist but not waterlogged. Feeding with a liquid feed every few weeks once the plants are established can help boost tuber development, compensating for a potentially shorter growing window.
Considerations for Soil and Location
Regardless of whether you plant in the ground or in containers, the location is key. Potatoes need plenty of sunlight – at least six hours a day is ideal for good tuber formation. If planting directly into the ground, ensure the soil is well-dug, free from weeds, and has good drainage. Adding some well-rotted manure or compost beforehand will enrich the soil and provide essential nutrients. However, avoid planting potatoes immediately after other solanaceous crops like tomatoes or peppers, as this can increase the risk of soil-borne diseases.
For July planting, aim to get your seed potatoes into the ground or containers as early in the month as possible to give them the maximum time to grow. If your ground is very wet or cold, containers are often the better choice, as the soil warms up faster.
What to Expect from a July Potato Planting
Planting potatoes in July means you are essentially aiming for a late autumn harvest. The success and yield will be different from a spring planting. Instead of large, mature tubers typically harvested in late summer or autumn, a July planting is more likely to yield 'new' or 'early' potatoes. These are smaller, tender tubers with thin skins, often considered a delicacy. This outcome is perfectly desirable if you're looking for a fresh supply of potatoes for roasting or salads in October or November.
The growth rate will depend heavily on weather conditions. Warm soil temperatures in July and August will encourage rapid establishment and initial growth. However, as the days shorten and temperatures cool in September and October, the plants' energy will shift towards tuber development. You might notice the potato plants blooming; this is a good sign that tubers are forming underground.
The primary advantage of planting potatoes in July is extending your harvest season into the cooler months with tender, new potatoes.
When to Harvest Your Late-Planted Potatoes
Determining the right time to harvest is crucial for potatoes planted in July. You’ll need to monitor the plants and the weather. Generally, 'early' and 'second early' varieties planted in July will be ready for harvest between 10 to 14 weeks after planting, depending on the specific variety and growing conditions. This usually places the harvest window from late October through to early December in many parts of the UK.
You can start checking for tubers about 10-12 weeks after planting. Gently scrape away some soil at the base of the plant to see how large the tubers are. If they are of a usable size for new potatoes, you can begin harvesting. You have a couple of options: either carefully ‘rob’ a few tubers from around the base of the plant, allowing the rest to continue growing, or dig up the entire plant for a full harvest. If a hard frost is predicted, it is advisable to harvest your potatoes before the frost hits, as it can damage the foliage and potentially the tubers themselves.
Potential Challenges and How to Mitigate Them
One of the main challenges when planting potatoes in July is the reduced daylight hours and cooler temperatures that occur as autumn progresses. This can slow down growth and reduce the final yield compared to a spring planting. Pests like slugs and snails can also be more active in the damp conditions of late autumn, so keeping an eye out for them and taking appropriate measures is important.
To protect your late crop from early frosts, keep a layer of straw or horticultural fleece on hand. You can cover the plants if a sudden cold snap is forecast.
Another potential issue is blight, a fungal disease that thrives in warm, humid conditions. While less common for new plantings in July than for crops already established over summer, it's still a possibility, especially in wet weather. Choosing blight-resistant varieties, ensuring good air circulation around the plants, and prompt removal of any blighted foliage can help manage this risk. By being aware of these potential challenges and taking proactive steps, you can significantly improve your chances of enjoying a successful late potato harvest from your July planting.