Why Do You Put Weight on Microgreens?

The addition of weight to developing microgreens has been shown to promote consistent germination, faster growth, and healthier crops. 

The rest of the article will go into detail about the benefits of putting weight on microgreens after sowing your seeds, how this results in a better crop, and how you can implement this strategy effectively at home.

Why should I put weight on seeds for microgreens?

The addition of weight pushes the seeds deeper into the growing medium, encouraging stronger and more consistent roots across the batch. The root hairs are forced to reach below the surface into the medium, which increases the stability of the crop.

How does weight benefit growing crops?

By forcing roots to grow downwards into the medium, the growing seedlings gain greater access to the vital nutrients, water and oxygen contained within it. This ensures the growing plants have all the required materials for further development. 

How does adding weight improve germination?

The pressure on top of the seeds helps them to shed their hulls. The weight on top of the seeds decreases air space, preventing their hard outer casings from drying out. It increases humidity as moisture is trapped and driven into the enclosed medium. 

Why is humidity important to seeds?

Seeds cannot germinate when they are deprived of moisture. Water is absorbed by the seeds to soften the hulls, which allows for the emergence of radicles and root growth.

Why does adding weight result in a more consistent yield?

The weight traps water within the medium as it had been originally distributed. If you water your seeds evenly before adding your weights, they will continue to have equal access to the resources required for germination. This ensures your plants develop at the same rate across your batch and decreases the number of seeds that do not germinate.

Does adding weight lead to healthier plants?

Plants are stronger and better-developed due to pushing against the added weight whilst growing. This leads to microgreens growing thicker stems that support greater growth. These stems can carry and transfer more nutrients and water needed for photosynthesis.

Why should I cover seeds with weights?

Seeds that are covered with weights are also deprived of light, which provides optimal conditions for germination. Horticulturists at the Pennsylvania State University Extension have shown that most seeds germinate best in darkness. 

Why can I not bury the seeds instead?

Microgreens that have been buried in soil are difficult to harvest and require thorough rinsing, which is time-consuming and inconvenient. The addition of a cover and weight simulates the environment seeds would be exposed to had they been buried in soil, without coating the shoots in troublesome dirt.

Why do seeds need darkness to germinate?

Light reacts with the surrounding gases and the seeds, causing their outer cases to harden. The hulls are dried out when exposed to light and the overall humidity of the seeds’ environment is decreased. This prevents the all-important shedding of hulls and growth of radicles needed to develop roots.

How does adding weight benefit growers of microgreens?

The time required for the growth of microgreens from seed to harvest is greatly reduced as a result of using weights. Seeds germinate evenly and quickly, and crops grown are healthy and easier to harvest due to the concealment of the roots. 

When should I put weight on my microgreens?

Weight should be added on new trays of microgreens after you have sown your seeds. The length of time you will need to keep your tray covered with the weight will vary according to the species of seed used. Faster growing microgreens such as will need two to three days of cover, whilst slower microgreens such as need five to eight days.

When should I remove weight from my microgreens?

Once seeds have sprouted, they usually require three to four days of continued light deprivation. The weight should then be removed at regular intervals after this time period to expose the growing plants to either sunlight or artificial light. The microgreens will struggle to develop further if they do not have access to the light required for photosynthesis.

How can I put weight on my microgreens?

New trays of microgreen seeds can be covered with a second tray containing your chosen weight. The amount of weight required depends on your chosen species of seeds and the unique conditions of your growing environment.

What do I use to add weight?

You can top your second tray with any object of your desired weight that applies an even amount of pressure across the seeds beneath it. There are numerous objects available that will achieve this including sandbags, large rocks, and containers filled with water.

What amount of weight should I use?

The ideal amount of weight for your seeds will vary according to species, medium, and growing environment. It is best to experiment by having multiple batches of the same seed variety under different weights and seeing which yields the best results for you.

Is it normal for microgreens to have yellow leaves?

Microgreens that have grown under a weight have yellow leaves and this is not a bad sign. Chlorophyll contained within the leaves and stem react with light to produce the plant’s green pigment. Once the chlorophyll is exposed and able to photosynthesize, the plant will quickly attain a healthy green colour.

Can I continue to use weights after germination?

It is beneficial to continue putting weights on trays of microgreens after germination to encourage the growth of strong shoots. Trays should be exposed for twelve to fifteen hours a day to give plants access to light and resources for growth. They can then be covered with weights for nine to twelve hours to mimic night-time. 

Do all microgreens benefit from adding weight?

The amount of benefit your microgreens will gain from growing under weight depends on the species of seed used. Whilst most seeds do thrive under pressurized conditions, some varieties such as broccoli seeds seem unaffected by additional weight. Therefore it is important to experiment and discover what works best in your unique conditions.