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How to Grow Micro Arugula







9+ days (using grow lights)

3 days

stacked with light weight



  • 3 Bootstrap Farmer microgreen trays

  • 2x trays without holes + 1x tray with holes​​

  • Grow medium​

  • we recommend loose coco coir​

  • Water & sprayer​

  • in the absence of a water source with spray nozzle, we recommend a pressure sprayer​

  • SowYummy Arugula seeds

  • 1 portion per 1010 tray, or 2 portions per 1020 tray

  • Clean shaker​ - optional, but recommended​ for sowing Arugula seeds​​

  • we recommend a small shaker such as a glass spice bottle (eg. from ginger powder) or shaker with small holes (such as a stainless steel sugar shaker)

  • Anti-fungal spray

  • 5-10 lb weight

PRO TIP Avoid plastic shakers as they create static making it cumbersome to shake out the seeds


If using a medium other than loose coco coir, prepare it according to manufacturer's instructions.

Nest the tray with holes inside one tray without holes.

Pack the tray with coco coir about 3/4 full. We use approximately 2 1/4 litres of loose coco coir in each 1020 tray or 1 1/4 per 1010 tray. If the tray is too full this will allow too much light in and impede germination, but if it's not full enough harvesting will be more difficult.

Be sure to distribute the coco coir as evenly as possible throughout the tray and into the sides and corners to ensure good water retention.

Gently press the second tray without holes over the top of the coco coir to even out the surface. You don't need to press too hard, we are not compressing it just smoothing it out. Don't worry about the minor channels created by the tray, these will smooth out during watering and don't affect germination or growth.


In a pinch you can use a spray bottle for this step, however, to ensure adequate saturation a spray bottle will be onerous.

Using your pressure sprayer set to medium/light intensity, spray over the grow medium in a zigzag pattern from edge to edge, starting at the top of the tray, slightly overlapping each stroke. We find that 2-3 passes over the tray are sufficient.

The medium needs to have enough water to sustain germination for about 3 days, but not be so wet that fungus will grow or that young shoots start to rot while in germination. Think damp not soggy.

To check if your medium is adequately saturated, make a small hole in a corner of the tray with your finger. The coco coir should be wet all the way through but not dripping into the bottom tray.

PRO TIP If you're working indoors and are concerned about water on floors or other surfaces, place your tray inside an adequately sized storage bin to contain the overspray.


Using a shaker, broadcast seeds as evenly as possible all over the grow medium.

Avoid clumping as that impedes air circulation and air circulation is vital to the health of your crops. Fungus and​ damping off disease are common in environments with poor air circulation.

Give the seeds a light misting of water to activate them. We like to use an anti-fungal spray instead of plain water because Arugula is prone to mold and damping off.

Arugula seeds are mucilaginous which means that once wet, they develop a sticky jelly-like coating (in the same way chia seeds do) so avoid touching them with wet hands or after misting.


Stack the second tray without holes ​in a nesting position over the sown seeds. Place your light weight on top.​ A couple of large mason jars full of water work great, we found that too much weight on Arugula contributes to moulding in the center of the tray.

Place the tray in a cozy area where it can stay undisturbed for a few days. A temperature of at least 20 degrees Celsius (68 Fahrenheit) is needed for healthy and even germination.

PRO TIP If heating your space is not an option, you can use a seedling heat mat under your tray.

Refrain from peeking under the stacked tray for the entirety of the 3 day germination period. Because of their mucilaginous nature Arugula seeds will stick to the top tray and lifting it will disrupt the radicles trying to anchor the seed to the grow medium.

PRO TIP When calculating germination/grow cycle days, we consider the day you planted your seeds as day 0.


By the third day you should see microgreens poking out around the edge of the tray, maybe even lifting the top.

At this stage some growers will put the crop into blackout to make the mcrogreens taller. We don't recommend this for Arugula because it is prone to fungus and damping off disease, so it's best to get it under lights and exposed to air at this stage.

Remove the weights and top tray and check your crop for any signs of problems. If all is well, place your microgreens under lights. Most of the microgreens at this stage will be yellow and a little wavy. With the weight off they will start to stretch towards the light, and as they photosynthesize they will turn green.

On the first day under light give your microgreens a generous bottom watering, almost a cup.

To bottom water, lift only the tray with holes and pour water into the bottom tray without holes, then lower the tray with holes. The grow medium and microgreens will absorb the water through capillary action.


You can grow your microgreens using other light sources but we recommend using complete spectrum LED grow lights.

Give your plants 16-18 hours of light every day.

PRO TIP Even plants need to sleep so if the space where you are growing your microgreens is exposed to sunlight, schedule the time your lights are off to coincide with nighttime.

Make sure you have adequate air circulation in the space where you are growing your microgreens.

Water your microgreens daily - a little goes a long way. It's better to lightly water your microgreens twice a day then to overwater them once a day.

Remember, air circulation is vital to the health of your crops. Fungus and​ damping off disease are common in environments with poor air circulation and overwatering.

The edges of the tray will likely dry out fairly quickly because they are more exposed to air. We like to mist close to the grow medium around the perimeter where we find dry areas, avoiding the canopy.

Arugula seed husks can sometimes stick to and dry on the stems of Arugula micorgreens. SowYummy seeds have been tested for pathogens (including those which cause food borne illnesses) so they are perfectly safe to eat.


We like to harvest Arugula microgreens at the cotyledon stage. In our experience they are most tender, flavourful and delightfully peppery during this time.

If you intended to store the harvested microgreens, make sure the canopy and stems are dry. Microgreens stored when wet will start to decompose quickly.

The best way to harvest any microgreens is using a clean and sharp knife.

Scissors can work fine if you are harvesting to serve, however, if you intend to store harvested greens, scissors are not recommended. This is because scissors tear the stem rather than cut it, and torn stems bruise and start to decompose much quicker than stems cut cleanly with a disinfected knife.

We disinfect our knives using a solution composed of 1 part 3% food grade hydrogen peroxide mixed with 2 parts filtered water.

To harvest Arugula microgreens, using one hand gently grab hold of a modest handful of their canopy (leafy tops) and slice the knife blade across the stems a little above the substrate to avoid picking up grow medium.

Store any microgreens in a clean airtight container in the fridge. If you are going to wash them, do so only when you intend to use them.

In our experience healthy, properly harvested and stored microgreens will keep in the fridge for at least 10 days.

Happy eating!

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