Growing sweet potatoes indoors is totally doable if you treat it like a warm-season vine: steady warmth, a big container, and patience. The bonus is you can grow it for greens (leaves) even if the tubers stay smaller.

Quick answer: grow sweet potatoes indoors

• Start with a healthy sweet potato and sprout it into slips (shoots)

• Plant slips into a large container with airy compost + extra drainage

• Give bright light and warm temps (sweet potatoes hate cold)

• Keep compost evenly moist, never soggy

• Harvest leaves anytime; harvest tubers after 90–140 days (variety + conditions)

Do this first: pick your warmest, brightest indoor spot (or shelf) before you start slips — sweet potatoes stall if they’re chilly.

Can you really grow sweet potatoes indoors?

Yes — but expectations matter. Indoors you’ll usually get:

• A big vine (fast)

• Edible leaves (easy win)

• Smaller tubers than outdoor ground-growing (still possible with the right setup)

If you mainly want a reliable edible indoor crop, it’s worth pairing this with fastest growing indoor vegetables for quicker harvests too.

What you need to grow sweet potatoes indoors

Before you start, here’s what makes the biggest difference:

• Warmth: ideally a consistently warm room (cool windowsills slow everything down)

• Light: bright window or supplemental light in darker months

• Container size: bigger pot = better chance of tubers forming

• Airy compost: heavy, wet compost = rot risk

A practical “easy mode” setup is a large breathable container like a fabric grow bag.

Step 1: How to make sweet potato slips indoors

You’re not planting the sweet potato itself (usually). You’re growing slips, then planting those.

1. Choose a firm sweet potato (no mould, no soft spots).
2. Sit it half-submerged in water (or in damp compost).
3. Keep it warm and bright.
4. Wait for shoots to grow to around 10–15cm.
5. Twist slips off and place them in water until they root.
6. Fix in 10 minutes: slips keep going mouldy in water

This usually happens when the water sits too long or the potato has a damaged patch.

• Refresh water every 1–2 days

• Use a clean jar

• Trim away any soft or damaged bits

• Move it slightly warmer (but not in direct heater blast)

If your home runs cool, gentle heat speeds everything up. A small seedling heat mat can be a game-changer for starting slips indoors.

Step 2: Best pot size and soil for indoor sweet potatoes

Sweet potatoes don’t like sitting wet, and they also don’t like being cramped.

Aim for:

• 30–50L container for 1–2 slips

• A compost mix that drains well (think “fluffy”, not dense)

A simple indoor-friendly mix:

• 70% multi-purpose compost

• 30% perlite or orchid bark (for airflow)

If you’re unsure what “good drainage” looks like indoors, your improve indoor plant drainage post is a perfect companion.

Avoid this mistake: planting slips too close

Crowded slips grow a jungle of vine but often form fewer tubers.

• 1 slip per medium container

• 2 slips max in a 50L bag (and only if you train the vines neatly)

Step 3: Light needs (and where most people go wrong)

Sweet potatoes indoors fail for one reason more than any other: not enough usable light.

They can survive as a leafy vine in medium light, but tubers need:

• bright window light, ideally several hours a day

• or extra light in winter / darker rooms

If you’re still building your lighting setup, link to your main hub: best lights for indoor gardening.

What to do if the vine goes long and leggy

That’s classic low light.

• Move closer to the window

• Rotate the pot twice a week

• Pinch the tips to encourage bushier growth

• Consider supplemental light if it’s winter or north-facing

Step 4: Watering and feeding sweet potatoes indoors

Sweet potatoes like consistent moisture, but they hate soggy compost.

Watering rule that works indoors:

• Water when the top 2–3cm feels dry

• Then water thoroughly and let excess drain away

Feed:

• Once the vine is actively growing, a light feed every 2–3 weeks is plenty

• Avoid very high nitrogen feeds (huge leaves, fewer tubers)

A simple option is a balanced liquid tomato fertiliser.

A useful trusted reminder:University Extension guidance on container-grown sweet potatoes backs the idea that warmth + well-drained compost matters more than heavy feeding.

Step 5: Training the vine indoors (so it doesn’t take over your room)

Give the vines a plan early:

• Train along a window frame (with clips)

• Let it trail from a high shelf

• Use a small trellis in the container

Quick win: harvest the leaves (greens)

Sweet potato leaves are edible (cook like spinach).
Harvest by pinching tips regularly — it keeps growth tidy and can reduce the “wild vine” problem indoors.

When to harvest sweet potatoes indoors

You’ll know tubers are likely forming when:

• The plant has had warmth + strong light for months

• The vines are mature

• You’ve kept watering consistent without waterlogging

Harvest timing:

• Usually 90–140 days after planting slips (variety + conditions)

Signs it’s time:

• Leaves yellowing naturally

• Growth slows down

• You’re approaching the end of your warm season indoors (or you’re done with the vine)

Tip: harvest gently — tubers can be smaller and close to the surface in containers.

FAQs

Can I grow sweet potatoes indoors just in water?

You can sprout slips in water, but you won’t reliably grow tubers in water alone. For tubers, you need compost and space.

How many slips should I plant per pot?

Indoors, 1 slip per medium container is the safest. Two slips only in a very large container with good light.

Why are my sweet potatoes only growing leaves?

Usually light is too low or the container is too small. Indoors, tubers are the “hard mode” outcome — leaves are the easy one.

Do sweet potatoes need full sun indoors?

They need the brightest light you can give them. A bright window can work; winter setups often need extra light for strong growth.

Are sweet potato leaves safe to eat?

Yes — cook them like spinach. Harvest small amounts regularly rather than stripping the plant.

Final Thoughts on Growing Sweet Potatoes Indoors

If you want the best chance of tubers indoors, focus on three things: warmth, light, and container size. Even when tubers stay small, you still get a fast-growing vine and edible greens, which makes this a solid indoor edible project.

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