Runtz XL Auto Grow Diary and Strain Review

This run was my second chance with Runtz XL Auto from Sweet Seeds. I’d grown one seed of this strain before and liked the finished flower, so this time I wanted to see how it would behave from a cleaner start.

The plants had 100% germination, grew with confidence, and handled training better than I expected. I used a big 50l (13.2gal) container, ran the lights on 22/2 early on, and set up automatic irrigation because I didn’t want the moisture level swinging too much.

Extra Seeds

17 - 25% THC

Runtz XL Auto (Sweet Seeds)

• Autoflowering
• Zen without meditation
• 400 - 550 g/m² indoors
  50 - 175 g/plant outdoors

Pack (number of seeds)

3+1

5+2

3575.38 ₹ 5921.72 ₹ 6256.91 Save 335.19

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Starting the Run

Grow Notes

The first setup was built around keeping the root zone active without making the run too fussy. I used compost tea as the main feed later on, and the early light schedule stayed long enough to keep the seedlings moving.

At the very beginning, the plants were only about 2cm (0.8in). Nothing dramatic was happening yet, which was fine by me. The goal was to let them establish and not overreact to every small change.

Week 1

The first week was mostly observation. The young plants looked stable, and I kept the environment gentle while they settled into the container.

There wasn’t much to correct yet. With autos, that quiet start can be a good thing, because losing time early usually shows up later.

Week 2

By week 2, the plants were around 10cm (3.9in). Growth was still compact, but the new leaves looked healthy enough that I stayed with the same basic routine.

I didn’t try to force training too early. The plants needed a bit more structure before bending would make real sense.

Week 3

The plants were still building their frame, and the grow started to feel more active. The automatic irrigation helped keep the medium from drying unevenly, which made daily care easier.

At this stage, I was mainly waiting for enough side growth to begin shaping them properly. They looked steady, just not ready for heavy handling yet.

Veg Progress and Training

Week 4

Week 4 brought a real jump. The plants reached about 65cm (25.6in), and I started using LST more seriously to keep the tops spread out instead of letting everything shoot upward.

That stretch made the grow more hands-on. Runtz XL Auto wasn’t difficult, but it clearly wanted room, and I had to keep guiding the branches before the canopy got away from me.

Week 5

Humidity dropped again at the start of the week, so I had to improvise. I put a towel under the drain area and another wet towel inside the space, then aimed one irrigation dripper at the towel so it would stay damp.

That worked better than expected. Humidity climbed to 65% by midweek and reached about 70% near the end. The plants were still in veg, with no pistils showing yet, so I did another round of LST and defoliation on days 31 and 35.

Feeding stayed simple: compost tea diluted with water at 1:10. The plants were around 35-40cm (13.8-15.7in) and looked healthier after the room settled down.

Week 6

This was the week where growth really took off. In 7 days, the plants nearly doubled and reached about 70cm (27.6in).

I did have one annoying accident. While checking the box, I knocked the fan and it fell onto the plants. A few branches broke, but the root zone was fine and the environment was still under control, so I didn’t treat it like a disaster.

Flowering was only just beginning now, which told me the run would take longer than the 8 weeks listed on paper. From the look of the plants, they still had at least 6-7 weeks left.

Week 7

By week 7, Runtz XL Auto was filling the box fast. The plants had a sativa-style structure, with long internodes, narrow leaf fingers, and a lighter green color.

There weren’t many side shoots, but the ones that did form were long and kept reaching for the light. Because the planting was dense, I had to remove leaves almost every day so light could reach the lower flowers.

That part got tiring. Without the daily cleanup, only the top flowers would have developed properly, and the rest would have stayed as tiny popcorn. I kept giving 100ml (3.4fl oz) of compost tea every day, and the plants seemed to like it.

The Flip and Early Flower

Week 8

Week 8 started with one more defoliation, and after that I decided to stop removing leaves for a while. The plants had already been worked enough.

The flowers were starting to look more serious, and the smell finally appeared. It was the first point where the grow felt less like plant management and more like watching the buds take shape.

Week 9

The plants reached about 120cm (47.2in), which was more than enough for the space. The canopy was still manageable, but it needed attention because the upper growth kept trying to dominate.

At this stage, I focused on keeping light moving through the plant rather than chasing a perfect shape. The lower flowers had a better chance now, and that was the whole reason for all the earlier leaf work.

Week 10

I moved into a flush this week and stopped trying to push the plants harder. The flowers were already formed, and the main job was to let them finish without adding more stress.

The structure still looked a bit wild, but it made sense for this run. Runtz XL Auto had stretched hard, and I was glad I started training before flowering got too far along.

Week 11

Week 11 was quieter. The plants kept ripening, and I mostly watched how the flowers were changing instead of making new adjustments.

After the earlier fan accident and all the defoliation, I was happy to let them finish in peace. They didn’t look fragile, but there was no point in testing them any further.

Late Flower and Finish

Week 12

Late flower was mostly about patience. The buds were close, but I didn’t want to cut too early just because the plants had been standing for a while.

The smell stayed sweet and fruity, and the flowers looked much better than they would have if I had left the lower canopy buried under leaves.

Week 13

The finish came after a longer cycle than the strain description had led me to expect. That didn’t bother me much in the end, because the plants had stayed productive and the quality looked worth the extra time.

I let the final days pass without more training. By then, the work was done, and all I needed was a clean finish.

Grow Notes

This grow reminded me that Runtz XL Auto can be a strong plant in a tight space, but it still asks for regular attention. The daily defoliation during the busiest stretch wasn’t fun, though it probably saved a lot of lower flower from turning into useless popcorn.

Runtz XL Auto Yield and Final Thoughts

I’m glad I gave Runtz XL Auto another try. The plants grew steadily, responded well to LST, and didn’t fall apart after a few rough moments in the room.

The finished smoke was thick and sweet, with fruity tropical notes behind it. It wasn’t a light, casual effect for me. The high hit the head fast, pushed my mood up hard, and made talking feel almost too easy.

I’d call the effect creative and social, but not something I’d hand to a complete beginner without warning. It has power behind the sweetness.

For tight indoor conditions and a grow where I didn’t want to micromanage every input, Runtz XL Auto made sense. I wouldn’t say it was zero-maintenance, because the canopy work was real, but the final flower made the extra attention feel justified.

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