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Potatoes are a hungry crop that need lots of nutrients throughout the growing season. A failure to fertilize potatoes properly is a common issue among growers and it impacts any potential harvest.
Setting up the right feeding schedule is easy, and using a feed that is high in phosphorus and potassium will help you get the biggest and best tubers.
There are a lot of different kinds of potatoes to choose from, and growing them is pretty easy. If you remember how and when to fertilize potatoes, you can get the biggest crop possible for your work.
Potatoes are a hungry crop that requires lots of water and nutrients to grow( credit: Getty/johnnyscriv)
Drew is a former professional gardener who specialized in growing vegetables for many years. He worked in historic kitchen gardens in the UK and grew a wide range of edibles for chefs. Potatoes were a staple annual crop in the productive gardens. He has also grown vegetables at home – including potatoes – in raised beds and containers.
Growing a bountiful crop of potatoes takes more than just planting the seed potatoes in the ground To get the largest, healthiest potatoes at harvest time requires properly fertilizing the plants throughout the growing season Fertilizer provides essential nutrients that potato plants need to grow vigorously and produce loads of tasty tubers. But when and how often should you fertilize for the best results?
Why Fertilizing Potatoes is So Important
Potatoes are heavy feeders that deplete nutrients quickly from the soil They require consistent fertilization to replace depleted nutrients and drive growth. Without proper fertilization, plants will struggle to grow and produce potatoes
Some key reasons why fertilizing potatoes is critical:
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Promotes Foliage Growth Nitrogen in fertilizer fuels leaf and stem growth above ground More foliage means more photosynthesis and plant energy to grow potatoes
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Drives Tuber Bulking: Phosphorus and potassium in fertilizer bulk up the potatoes underground. These nutrients go straight to developing big, robust tubers.
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Replaces Depleted Nutrients: Potatoes rapidly take up nutrients from the soil. Fertilizer replenishes nitrogen, phosphorus, potassium that plants have used.
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Supports Overall Plant Health: Proper nutrition keeps plants vigorous and better able to resist diseases and pests.
Without fertilizing, potato plants often struggle to size up potatoes for harvest. But with the right fertilizer at the right times, you can maximize yields.
When to Start Fertilizing Potatoes
Potato plants need fertilizer throughout the growing season for nonstop nutrition. But when should you actually start applying it?
Pre-Planting
It’s smart to fertilize potato ground a few weeks before planting seed potatoes. Spread 1-2 inches of aged compost or manure over the soil and dig it in. This organic matter boosts nutrients for sprouting plants.
You can also apply a balanced granular fertilizer like 10-10-10 before planting. Just be sure to water it into the ground.
2 Weeks After Planting
Don’t fertilize potatoes right at planting, as the sprouting seeds don’t need it yet. Wait until plants are 2-3 inches tall, about 2 weeks after planting.
At this point, plants are established and ready for fertilizer to spur vegetative growth. Side-dress plants with a nitrogen-heavy fertilizer like ammonium nitrate.
4 Weeks After Planting
Apply a balanced fertilizer like 10-10-10 again 4 weeks after planting potatoes. This keeps nutrition steady as plants start to rapidly bulk potatoes underground.
The key is to fertigate by watering in the fertilizer right after applying. This carries nutrients down to the root zone.
How Often Should You Fertilize Potatoes?
Once potatoes are growing, they need consistent fertilizer every 3-4 weeks. A monthly application keeps nutrients available as plants expand foliage and enlarge tubers.
Here’s a schedule for fertilizing growing potato plants:
- 2 weeks after planting – Nitrogen fertilizer
- 4 weeks after planting – Balanced fertilizer
- 6-8 weeks after planting – Balanced fertilizer
- 10-12 weeks after planting – Balanced fertilizer
- 14 weeks after planting – Stop fertilizing
Make sure to water in fertilizers after applying. Granular or liquid fertilizers both work, just check rates on packaging.
The key is providing a steady feed of nutrients on this monthly schedule. This replaces depleted soil nutrients and powers vigorous growth.
How to Properly Fertilize Potato Plants
Here are some tips for fertilizing potatoes correctly to maximize growth and yields:
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Pick a Potato-Friendly Fertilizer: Look for fertilizers with more phosphorus and potassium than nitrogen, like 5-10-10. Too much nitrogen causes excess foliage.
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Follow Package Directions: Note correct application rates and timing instructions. More isn’t always better with fertilizer.
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Water In After Applying: Always water after applying fertilizer to move nutrients into the soil where roots can access it.
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Avoid Foliage Contact: Prevent fertilizer granules from touching leaves, as it can burn. Wash off any accidental contact.
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Use Lower Rates More Often: Smaller doses every 3-4 weeks work better than heavy fertilizing all at once.
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Stop 2 Weeks Before Harvest: Discontinue fertilizer in late season so potatoes don’t rot in ground before digging.
Following package instructions for correct products and rates ensures plants get proper nutrition without issues.
What Nutrients Do Potato Plants Need?
The three primary macronutrients that all plants require are nitrogen (N), phosphorus (P), and potassium (K). Potato fertilizers should contain some blend of these nutrients.
Nitrogen (N) promotes healthy foliage growth above ground. Leafy plants produce more energy to grow tubers. But too much nitrogen boosts vines over potatoes.
Phosphorus (P) aids in root, tuber, and overall plant growth. Phosphorus is extremely important for potato bulb development and maturity.
Potassium (K) is key for tuber quality and disease resistance. Potatoes high in potassium store better and have improved flavor.
Again, fertilizers with more phosphorus and potassium than nitrogen (like 5-10-10) are ideal for robust potato growth.
Signs Your Potatoes Need More Fertilizer
How can you tell if your potato plants are hungry for more nutrients between fertilizer applications? Watch for these signs:
- Slow or stunted foliage growth
- Yellowing or pale leaves
- Lack of flowers and potato formation
- Small, weak stems above ground
- Poor tuber development underground
Plants lacking nutrition won’t thrive. They become undersized and unable to produce a healthy potato harvest. Fertilizing more frequently fixes nutrient deficiencies.
Stop Fertilizing 2 Weeks Before Harvest
It’s crucial to stop fertilizing potato plants 2-3 weeks before your planned harvest date. This helps in two ways:
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Nutrients late in the season can cause potatoes to rot before harvest.
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Dry conditions make for much easier potato digging and cleanup.
Discontinue all fertilizer and watering in late season. Let plants naturally die back as tubers finish maturing.
Get Big Potato Harvests with Proper Fertilizing
Potato plants are heavy feeders that need consistent nutrition for optimal growth. Fertilize plants every 3-4 weeks from planting until 2 weeks before harvest. Use a quality potato fertilizer following package rates.
With the right schedule and fertilizer, your potato plants will have all the nutrients they need to produce abundantly right up until it’s time to dig those spuds. Proper fertilization leads to more potatoes and bigger tubers at harvest time.
When is the best time to fertilize potatoes?
Before you plant your potatoes, you do an important part of the fertilizing process for the crop. Applying manure to the planting area in the fall before planting potatoes in the spring has been done for a long time.
By applying this early, a lot of the extra nitrogen in the fresh manure will have broken down before the potatoes are planted. It also adds nutrients and organic matter to the soil. This can help prevent a common potato growing problem caused by giving the plants too much nitrogen. Too much nitrogen can make plants’ leaves grow quickly and make them focus all their energy on that instead of making tubers.
That early, even before you’ve started chitting your seed potatoes, is not the right time to use fertilizer. You could also use a potassium-rich slow-release all-purpose fertilizer, like Dr. Earth All Purpose Fertilizer, which you can buy on Amazon, and spread it on the growing area a week or two before you plant the potato tubers in the spring. The addition of feed prior to planting is especially important when growing potatoes in containers.
The exact timings for planting will depend on the type of potatoes you are growing. Late season potatoes are planted at the end of spring, while early season potatoes are planted in the beginning of spring. For every type of potato you can grow, you need to use fertilizer. Applying a slow-release fertilizer right before planting should give the plants fuel for at least the first month.
When plants are about six inches tall, that’s when you should start hilling them up. Author and editor of Amateur Gardening, Garry Coward-Williams, says that now is the time to start fertilizing regularly because the potatoes need a lot of water and nutrients to grow big tubers.
He also says, “They will grow better with a little help from a liquid plant food with high phosphorus and potassium levels every once in a while.” ‘Any of the tomato feeds are ideal for the job. Every two weeks until they are ready to be dug up, I give my potato plants a lot of water with liquid fertilizer added. ’.
The plants should not be fed or watered for at least two weeks before you plan to harvest the potatoes. A sign of when to stop watering and fertilizing would be the potato foliage starting to turn yellow. You stop watering to prevent any fungal infections and also to make harvesting the tubers simpler.
Consider adding fertilizer when hilling potatoes up( credit: Getty/digihelion)
Why is it important to fertilize potatoes?
All plants need the three key nutrients of nitrogen, phosphorus, and potassium for healthy growth. These nutrients are referred to as NPK and shown on labels as three plant fertilizer numbers. You will see these numbers separated by dashes that refer to the make-up of NPK, eg. 10-10-10.
Mark V Wessel, Director of Horticulture Research for Gardens Alive, hails fertilizing potatoes as an essential task for anyone wanting to grow the best crops. He says: ‘Proper fertilization is key to producing abundant and high yielding tubers. They are heavy feeders and if not given the nutrients they need, yields will be low, tubers small and possibly malformed and storability can be affected.’
Fertilizing potato plants will give you bigger potatoes and more of them( credit: Getty/Md Didarul Islam / EyeEm)
When to Fertilize Potatoes for Maximum Yield
FAQ
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