If you are like me, growing vegetables during the late fall and early spring can be a challenge. While my winters are really not that bad, they do require a cold frame for proper production without fear of going out to the garden and finding the fruits of my labor frozen.
Believe it or not, broccoli raab has growing requirements much like broccoli. It likes cool temperatures and can tolerate a light frost but when the weather warms, it will send up a flower stalk. Once this happens, the growing season for your broccoli raab is over.
To begin the planting process, let’s start off with a spring planting. Believe it or not, to get the most from your broccoli raab you will need to get it in the ground as soon as the weather warms in early spring. What does this mean? Well, the soil needs to be warmed to 40 degrees Fahrenheit. Once that has happened, you are ready to go out to the garden and begin to work.
The first step of this process is to select the best location for your broccoli raab. This vegetable like a sunny location but can tolerate some shade. The latter condition will delay maturity. Next, you will need to make sure that the soil is well draining and has a pH level of 6.0 to 7.5. If the pH is not correct, address the issue according to the pH level to bring it to the proper level for broccoli raab.
Once the environmental conditions have been met, the next step is to prepare the garden space. First, you will need to remove any unwanted plant material and loosen the soil. After the soil has been loosened, add a good amount of well seasoned compost and mix in.
Now that the soil has been prepared, the next step is to make the rows for your broccoli raab. While this step is not necessary since some people just broadcast the seed, I prefer to make rows. The rows themselves help reduce fungal problems that can arise during the growing season.
To make your rows, pull out some stakes and string. Push one stake in the ground and tie a string to it. Run this string down the garden space to the other stake you have a placed in the ground at the end of the garden. This is now your first row. Continue this process with additional rows that are 18 to 24 inches apart. After all the rows have been lined out, you can either leave them up or mark the area with powdered milk.
The next step is the planting process. While it is recommended that you plant a seed every inch, the problem with this approach is the fact that you have to go back and thin the plants out. If you are a frugal gardener or short on gardening time, consider planting your seed at the thinning space, which is 4 to 6 inches. As the seeds are planted, cover with ¼ to ½ inch of soil and water in gently.
Broccoli raab seed will germinate when the soil’s temperature is between 45 and 85 degrees Fahrenheit. Once that temperature has been reached, you should begin to see little green dots of growth in 4 to 7 days.
To help extend the broccoli raab growing season, consider planting your tomato plants alongside this vegetable. The shade from the tomato plant will keep the soil cooler and perhaps aid in another harvest of broccoli raab before it blooms.
Once the flower stalk appears, pull up the plant and compost.
While there are a few pests that attack broccoli raab, one approach to use to avoid problems is to set up row covers in the beginning of the season. Prior to the weather warming up, remove the covers to prevent heat buildup.
But whether you set up the row covers or not, there are other ways of dealing with the 4 common pests that can be found on broccoli raab. Cabbageworms are the same worms that feed on cabbage. The easiest treatment beyond the row covers is to simply hand pick off the worms when you see them. Flea beetles are simply restricted by controlling weeds that are around the garden space. Cabbage aphids can be taken care of by just spraying off the plants as needed. A burst of water is enough to dislodge the cabbage aphids. Also, invite beneficial insects like lady beetles to the garden space.
This last pest is one that does not have a solution and that is the cabbage root maggot. This pest feeds on the roots of the broccoli raab and will eventually cause the plant to wilt and die.
Now that we know how to plant broccoli raab in the spring, let’s take a look at how to grow it in the fall. The growing process is the same but with one exception. While this vegetable can tolerate light frosts, it does not do well with killing frosts. A technique by which you can use to grow this vegetable when the temperature dips is mulching. A deep layer of straw over your broccoli raab will sufficient to protect it during periods of heavy frost. Once the frost has passed and the weather has warmed, remove the straw mulch from the broccoli raab and allow it to continue to grow. At this point, you may be wondering why this technique would work. Broccoli raab is actually a biennial in its native country. A biennial is one that produces vegetation the first year and then a flower stalk the second year. Once the flower stalk is produced, the plant dies. In this example, adding the mulch allows the plant to grow more like a biennial since the mulch insulates it from the bitter cold.
Beyond using other plants for shade and mulching, there is one more way by which you can extend the growing season of broccoli raab and that is through proper harvesting. To get the most out of this vegetable, make sure to cut the leaves and “head” to ground level. Harvesting this way will encourage the plant to produce more leaves and as long as the weather remains cool, this process will continue.