various types of lettuce growing in a salad box
Updated: March 4, 2024

How long does it take to grow salad greens in a salad table or salad box?

Salad greens will grow:
2-3 inches in height in 12-24 days (micro-greens)
4-6 inches in height in 25-40 days (baby greens)
6-10 inches in height in 40-60 days (mature size)

This all depends on...

  • the crop-- lettuce and arugula will grow faster and taller than spinach or chard
  • spacing-- allowing more space between plants will allow them to grow larger
  • time of the season-- basil, beans, amaranth, and chard will grow faster in the summer.  All of the other salad greens will grow best April-June and September through October.
  • weather conditions-- for example, warm weather will speed up growth; very rainy weather could reduce growth.

What’s the best way to plant?

  • First, fill your Salad Table with growing media and level it off (don’t pack it). Seeds should be planted in straight rows (furrows) that you create by pressing the sections of 1X4 scrap wood (the excess from cutting the bottom support boards) into the growing mix.
  • Each Salad Table has 3 sections that are 17 5/16 in. X 30 in. The rows should be about 4 in. apart. You can either make 4 rows 30 in. long OR 7 rows 17 in. long.
  • Now for the fun part! Lay the yardstick on its edge over the furrow to help you space the seeds correctly.  Shake some seeds into a folded index card and tap them out into the furrow so they are about 1 in. apart.  Or, tap some seeds from the packet into your hand and use your thumb and forefinger to drop the seeds into the furrow.  Many of the crops have dark color seeds making them harder to view against the dark color growing mix.  Some of the lettuce seeds are white making them easier to see. The round seeds tend to bounce so keep the index card close to the growing mix.
  • Cover the seeds with about ¼” deep by gently brushing the growing mix from either side of the furrow.  Press down on the furrow with your fingers to make good contact between the seeds and growing mix.

What should I do with the extra seed?

Carefully re-seal or fold the seed packet. Keep all seed packets in a protected container indoors where they will be dry and at room temperature.

When will I see the new seedlings?

Members of the cabbage family (e.g. arugula, kale, mustard, broccoli) will germinate the fastest (2-4 days).  Lettuces are next (6-10 days).  Spinach, chard, basil, and cilantro will take 7-10 days to germinate.  Germination will be slower when the growing media temperature is below 50°F or above 80°F.

How far apart should the plants be?

Salad plants should be about 1-2 in. apart. There are exceptions: basil (4-6 in. apart), beans (3-4 in. apart).  It’s easy to sow the seeds too thickly. In that case, you simply remove excess seedlings to achieve the 1-2 in. spacing.  It’s OK to increase the plant spacing.  This will give you fewer, larger plants.

Removing excess plants is called “thinning.” You can gently pull the excess plants out by hand or cut them at the surface with scissors.  They can be composted, added to your salad that evening, or dropped on the ground.

Should I fertilize again?
Only if the plants are lighter green than normal and growing slowly.  In most cases, the one application after seedlings emerge will be enough.  You’ll add more fertilizer before planting the 2nd crop.

Fertilizing salad tables or salad boxes

Commercial growing media and compost do not contain enough nutrients to produce high yields of salad greens over a growing season.  Incorporate a dry fertilizer into the growing media - one that contains nitrogen, phosphorous, and potassium.  If the growing mix used is 50% compost, reduce fertilizer amount by 1/2 and don’t fertilize until plants are up and growing. To prevent leaf burn, wash off any fertilizer that lands on leaves and don't apply fertilizer when leaves are wet. Fertilize according to label directions. The following fertilizers will work fine: alfalfa meal, cottonseed meal, organic garden fertilizers, Osmocote, kelp meal. You can also apply liquid fertilizers like compost tea, seaweed extract, soluble chemical fertilizers (like MiracleGro, there are many others), etc.

The following fertilizers were trialed at labeled rates:

Type Analysis          
Cottonseed Meal 6-2-1
Osmocote 18-6-12
Sea-Plus (liquid) 3-5-2

How much watering of my salad table or salad box will I have to do?

After sowing the seed you must keep the growing media moist. You probably will not need to water every day until after seedlings emerge. Then you’ll need to water daily using a watering can or water breaker attached to a hose. The salad table will need about one gallon of water daily and the Salad Box will need about one quart daily.

Can I re-use the soil for the second planting?

Yes, just add more if necessary to bring the level up almost even with the top of the frame.  Then mix in fertilizer before planting.

Still have a question? Contact us at Ask Extension.