How I grew sweet potatoes that can produce large, delicious, friable tubers

I just harvested purple sweet potatoes from the Yard. I was very excited and surprised when I got very large potatoes. They are as big as 3 times and 4 times longer than a Heineiken beer bottle. Unbelievable!

So what is the secret to making potato plants have such large tubers and wonderful tasting?

The most important thing is: Quality of soil!

Below are the main factors that make sweet potato growing successful and high yields and best taste:

1. Preparing good soil:

   
   

   For sweet potatoes grown in pots or containers, the soil should be loose, well-draining, and rich in organic matter. Heavy or compact soil can cause small or misshapen tubers.

   
   

   Sweet Potato Potting Mix

   • 40% high-quality potting mix

   • 30% compost or well-aged compost

   • 20% coarse sand or perlite (for drainage)

   • 10% coconut coir or peat moss (to retain moisture)

2. 
   

   Optional Soil Amendments

   Mix in the following per 5 gallons (about 19 L) of soil:

   • ½ cup worm castings

   • 2 tablespoons bone meal (for root development)

   • 1 tablespoon kelp meal (for trace minerals)

   • 1 tablespoon azomite (optional)

   
   

   Soil pH

   • Aim for a pH of 5.8–6.5.

   Tips

   • Use a container that is at least 15–20 gallons and 12–18 inches deep.

   • Avoid high-nitrogen fertilizers, as they encourage leaf growth instead of tubers.

   • Keep the soil evenly moist but never waterlogged.

   • Place the container in full sun (6–8+ hours daily).

     
     

   For growing in the garden : The cheapest way to prepare good soil:

I used 20% chicken or pig manures mix with 50% yellow clay sands and 30% topsoil.

Where to buy Yellow sand? Search local seller at facebook marketplace.

Clay sand or yellow sand contains a lot of minerals that sweet potatoes can absorb, it is the main factor to make the sweet potatoes having good taste.

But to make high yields, you need to mix clay sand with compost (cow or chicken manures and coconut coirs or peat moss) and topsoils.

There is another more leisurely way, which is to collect all the dry leaves in the garden, beat them into a pile, water them or use probiotics to decompose them faster. Then mix with topsoil and clay sand to make a good soil mixture.

You also use the yellow clay mix sands instead off using topsoils. Sweet potatoes like yellow sand with little clay a lot. You also can use garden lime if your garden soils were toxic, or low PH.

Picture: I made good soils from Pig manure (compost already), clay sands, dry leaves and food trashes compost.

2. Location to grow: Sweet potatoes like full sun, if you grow in shadow area, they wont produced Ube as you expected.

3. Sweet potatoes tend to sprawl widely across the ground and send out roots along their vines. Be sure to trim off these secondary roots so the plant can concentrate its nutrients on developing the tubers, which are its main roots

4. Water daily if it dry

The outcomes after 4 months growing?

Excellent !

Molokai sweet potatoes I grow with clay sand mix

Murasaki sweet potatoes

Okinawa Sweet Potatoes

Here are Okinawa, Molokai and Midwest sweet potatoes I grew by Clay sands mix topsoils and iI roasted by air-fry:

2. The funny, low cost way to grow

I use the used bag like these, filling with the good soil, then grow Sweet Potatoes vertically. It looks so amazing. My friend said it was the best idea to enjoy growing. You can see it grow up everyday right here, in the entrance, not in the backyard. Everyone could see it, not only you!

After 3-4 months, you can easily to harvest by tearing the bag. I am sure with you they will produce the big and delicious yams.