LED Grow Journal: Mars Hydro TSL-2000W vs Spider Farmer SF-2000

by Nebula Haze

This is the beginning of a cannabis grow journal featuring a grow-off between two LED lights:

Spider Farmer SF-2000


Mars Hydro TSL 2000W

Why these LED grow lights?

  • We’ve received lots of questions about Mars Hydro and Spider Farmer (more than other “quantum board” or “spread style” LEDs)
  • They are each company’s design for a 2’x4′ grow space (my favorite tent size)
  • Summer is about to start in California and they both run cool

LED Light Stats

I am very skeptical of those estimated yields by the manufacturer but I would be happy with half that. I’ll update this section with more differences between the lights as I gain more experience with them.

Setup details

Dyna-Gro "Foliage-Pro" is a proven cannabis nutrient option for the vegetative stagePlusDyna-Gro "Bloom" is a proven cannabis nutrient option for the flowering stage

Experiment Procedure

Vegetative Stage

Flowering Stage

  • Initiate flowering stage with 12/12 schedule when the entire grow space is filled and plants average about 12″ (30cm) tall
  • Defoliate lightly week 1 and week 4 of flowering
  • Also lollipop plants on week 4
  • As plants grow, remove any leaves that are laying on each other making wet spots (to prevent mold)
  • Otherwise, leave plants alone until harvest so any differences come from the grow lights

Day 1 (April 1, 2021) – Clones rooted and ready for transplant

Rooted clones get moved to cups today!

Mama plants with cuttings in the aerocloner. Now that the babies have made roots, time to start the experiment!



Day 10 (April 10, 2021) – Clones ready to be put in pots

The clones for this test are rooted and happily growing in paper cups. They’re ready to get transplanted to pots and put into their respective grow tents this week.

Strains are Zweet Inzanity, Amnesia Lemon, and Pacific Punch. I’ll pick the 2 most similar clones from each strain for this test.



Day 17 (April 17, 2021) – Clones transplanted into tents with grow lights

I did my best to pick two identical clones for each strain to try to make this trial as fair as possible. Here are the clones immediately after being transplanted to 5-gallon pots and put into their respective tents. I tied some branches down to help spread them out (which is why some branches appear sideways). I anticipate these plants are going to explode with growth now that they’ve got big nice lights and plenty of room for their roots to grow.

Spider Farmer on top (white labels), Mars Hydro on bottom (with red labels to help remember that’s the “Mars” tent)

More about the Spider Farmer SF-2000 setup

Spider Farmer tent at 24″ away

Here are the Spider Farmer light levels at 100% power

Lux meter shows bout 33,000 lux at 24″ away in center

Here are the results with an Apogee meter (measured in µmol m-2 s). There is quite a bit of variance between the middle and sides of the tent (between 478-567 µmol m-2 s), especially compared to the Mars Hydro, which you’re about to see next


More about the Mars Hydro TSL 2000W setup

Mars Hydro tent at 24″ away

Here are the Mars Hydro light levels at 100% power

Lux meter shows bout 40,000 lux at 24″ away in center

Here are the results with an Apogee meter (measured in µmol m-2 s). I’m pretty impressed as this light seems to put very similar amounts of light (between 564-594 µmol m-2 s) throughout the entire tent onto every plant

Clones seem happy so far! Can’t wait to see how they grow this week now that they’re in their respective tents.



April 23, 2021 (Day 23) – Clones are growing and being trained to grow flat and wide

The plants took a little time to get adjusted to the new LED grow lights (they were yellowing a bit on top) but now seem ready to enjoy them at 100%. There wasn’t much growth the first few days after plants were put in the tents but they’ve been exploding in growth the last few days.

The Spider Farmer plants seemed to have adjusted quicker but the Mars Hydro ones may catch up this week. I think by next week there may be a clear leader for vegetative growth, but I also know from past grow light experiments that the light that does best in the vegetative stage is not always the one that produces the best yields in the flowering stage.

I did some plant training to make plants more flat and wide. As far as nutrients I’ve been giving them 1 tsp/gallon of Dyna-Gro Foliage pro at 6.1-6.2 pH.  The two Pacific Punch plants (left) seem pale/hungry (they’re also the biggest and fastest-growing) so I’ll be giving that plant slightly higher nutrient levels for a few waterings to see if I can get it to the same perfect green color of the others.

Spider Farmer tent before and after spreading out plants

Here is the Spider Farmer tent a little later after the leaves had time to mostly stand back up. Spider Farmer is currently 24″ away.

Mars Hydro tent before and after spreading out plants

And the full Mars Hydro tent. Mars Hydro is 26″ away (I moved it up a little because the tops were looking a little bleached) but I will let them grow up to it now that they’ve fully adjusted

Still neck and neck!



May 1, 2021 (Day 31) – Initiate the Flowering Stage with 12/12 light schedule

Strains typically about double in size after the switch to 12/12 so I’ve been watching the plant height. The plants have grown quite a bit and finally reached half the final desired size which means it’s time to start flowering them.

Today I initiated a 12/12 light schedule to get them to start making buds. Next week they’ll get their first defoliation.

The plants in the Spider Farmer tent seem to be growing at about the same rate as each other, but I noticed in the Mars Hydro tent that the right plant (Zweet Inzanity) is falling behind while the left plant (Pacific Punch) is almost double its size. All the plants are getting the exact same amount of water and nutrients, and the same light level according to the PAR meter, so it’s just how that particular plant is reacting to the Mars Hydro.

As we initiate 12/12 today, the overall average plant size in both tents still seems about the same.

The real exciting part is going to be how they produce in the flowering stage.



May 8, 2021 (Day 38, Flowering Day 7)

Although the plants don’t have any actual flowers yet, I’m seeing lots of pistils (white hairs) popping up everywhere and the plants have been stretching. They’ve grown about 6″ taller in the last week, and also just bigger and wider.

I gave them Vegetative nutrients for the last week because plants do a lot of vegetative growth the first few weeks after 12/12 and I wanted to make sure they had plenty of Nitrogen to power their growth. But starting today I am giving flowering nutrients (Dyna-Gro Bloom at 1 tsp/gallon). When I add that to my tap water it automatically sets the pH to 6.2, so no need for PH Down! A nice little bonus. So far I’ve been pleased with the results from Dyna-Gro.

Plants got a lot bigger this week, but still pretty well matched. By next week we should have little mini budlets to look at.




May 14, 2021 (Day 44, Flowering Day 13)

Plants are chugging along and seem to be fully into the flowering stage now.

Finally seeing buds this week. Or more like “budlets” right now.

I defoliated the plants today to thin out the leaves as some were laying on top of each other creating wet spots. I also removed leaves that were covering bud sites. Learn more about my defoliation method for these plants.

Spider Farmer tent before & after defoliation

Mars Hydro tent before & after defoliation

I filled a 5-gallon bucket full of leaves but the plants were so bushy it barely looks like I took anything. I plan to do a more robust defoliation and lollipop around week 4. The idea is to take away parts of the plant that will never amount to anything in order to force the plant to put all energy into fattening main buds as opposed wasting energy all over the plant. Until then I’ll only remove leaves that are covering bud sites or creating wet spots. That’s because bud sites tend to fatten more when they get access to direct light, and wet spots can attract mold and powdery mildew.

From the pictures above it may not look like I defoliated much, but I filled a 5-gallon bucket with leaves



Stay tuned for the next update!


Return to Top of Page