How to succeed with transplanting crops

Young senposai transplant.
Photo Pam Dawling

I wrote very recently about Direct Sown Vegetable Crops

There I referred to my Nov 2021 post, Preparing for Spring Transplants  (handle replacements, seed compost, aphids, soil blocks, Winstrip trays).

I have written previously about the Advantages and Disadvantages of Direct sowing and Transplanting and also about  using Bare Root Transplants.

Here I am going to give many tips for success with transplants.

Succeeding with transplanted crops

Tomato transplants in pots, ready to plant out in mild weather. These are for our hoophouse. Outdoor tomatoes are started here in March.
Photo Wren Vile
  1. Grow good transplants: sturdy, not spindly; good size cells or good depth flats; grow enough plus 20% (less for kale, more for melons)
  2. Harden off for two weeks before transplanting: cold frame. Cooler temperatures, more breeze, brighter light.
Flats of transplants in our cold frame ready for transplanting.
Pam Dawling

3. Prepare the bed or row: detach all weeds (hoe). Loosen the soil (till or broadfork as needed).

4. Stale seed bed technique: water, hoe off the new weeds. Hoe the day before transplanting (easier to hoe soil without crop plants to work around). Or tarp to smother weeds. Or use an organic mulch to smother weeds, once the soil is warm enough for that crop.

5. Mark the row spacing with a row marker rake, or lines in the soil with the corner of a hoe, or stakes and string. Don’t plant too close to the bed edge, or navigating the path becomes tricky (and wet in the morning dew). To plant two rows of broccoli or chard in a 4 ft (1.2m) bed, I’d set the two rows 16-18” (41-46 cm) apart, with 16-15” (41-38 cm) between the row and the bed edge.

Johnny’s Bed Prep rake with row marker pegs.
Photo Johnnys Selected Seeds

6. Water your transplants well on the day before transplanting.

7. Check you still have enough plants for the desired spacing. This is your last chance to make the space between one plant and another bigger (if you have fewer plants now), or smaller (to fit in some extras, perhaps sacrificing the size of each head).

8. Either mark the spacing now, with a rolling dibble or using a measuring stick, or mark them as you go along transplanting. I prefer to offset the rows, so they are in a zigzag from each other, rather than have them square set, where the plants are directly opposite those in the next row. The offset method gives each plant the most even space all round before it encounters roots or leaves of its neighbor.

A bed of young transplanted lettuce, with plants in each row offset from neighboring rows. the plants form diagonal rows, easy for hoeing.
Credit Wren Vile

9. Plan to transplant late in the day, unless it is cool and overcast, or drizzling (“ideal transplanting weather”. The plants then have the cooler night to recover from the surprise of transplanting before facing hot or bright sunshine. It really makes a difference! You can get everything ready earlier in the day: shade cloth or rowcover and weights to hold it down, wire hoops if needed, watering equipment (cans or hose), labels, tools.

10. Water thoroughly again one hour before transplanting. This ensures the plant cells are holding as much water as they can before their roots or root hairs get a bit damaged during transplanting.

Transplanting spinach from a Speedling flat. Butter knives are the tool of choice for easing the little wedges out of the tapered cells.
Photo Denny Ray McElya

11. Pop a transplant out of its cell, holding it by a leaf if possible, not the stem (there are spare leaves, but no spare stems, and you want to preserve all the roots too). Develop a good technique in order to preserve the life of plastic cell packs. Perhaps tilt the cell pack diagonally and squeeze the bottom of a cell, pushing the plug upwards. Perhaps use a butter knife to slide down the side of a cell and flip the transplant upwards while holding the plant with your other hand. Some plug flats have holes in the bottoms of the cells, where you can push up with a finger or a dowel. All the soil/compost in the cell should come out with the plant. You are definitely not “digging” the plants out of the cells.

Transplanting bare-root spinach.
Drawing by Jessie Doyle

12. Or scoop a plant out of an open flat with a good handful of compost, keeping your hand under the root-ball. This gets easier once the first plant has been extricated.

13. Make a big-enough hole in the soil where you want to plant, without actually digging out any soil. It’s a waste of time to make a pile of soil. Try instead to insert the trowel to the correct depth and wiggle it back and forth to open up a slot. I like the Wilcox stainless steel trowels rather than the “traditional” wide scoop-shaped trowels for transplanting. We have Wilcox 102 and 104 models, and the smaller 50S.

Wilcox 12″ (30cm) 102 stainless steel trowel.

14. Slide the plant into the hole, keeping a hold with one hand, so you can set the plant at the correct depth. Use the trowel in the other hand to push or pull soil back into the hole until it is filled.

15. Press the soil down around the stem quite firmly. You don’t want compressed soil that won’t drain well, nor do you want loose soil with lots of air pockets, as these prevent roots from drawing water from the soil. Good root contact with soil is important. I was taught to take the end of a leaf after transplanting and tug gently. If the leaf tears, you have planted firmly enough. If the plant pulls out of the ground, try again.

16. For a long, satisfying gardening life, develop a technique where you don’t set the trowel down. Just keep it in one hand and do the other tasks with your other hand. This will be more efficient. Gardeners with only one working hand will have to ignore this piece of advice, of course.

17. If you have not pre-marked your planting spots, measure to the next spot. You only need to measure one row in the bed, as it works better to eyeball the other rows.

18. Continue until you have been transplanting for 20 minutes, or 30 minutes in cooler overcast conditions, then pause and water in what you have planted.

19. Some people prefer to have a watering can beside them and water each plant immediately after planting. If conditions are very hot, this is definitely best. Otherwise, I make faster progress in 20-30 minute sections. Another alternative is to use a hose with a valve on the end. The goal is 6-12 seconds of water per plant, depending how free draining your soil is and how fast the water is flowing.

Spring cabbage planted in hay mulch, a few weeks after transplanting.
Photo Kathryn Simmons

20. Remember, with transplanting, you have the opportunity to select the sturdiest plants and leave the wimps in their cell or a corner of an open flat, for replacing casualties in a week. Really poor specimens can be thrown over your shoulder!

21. When you finish planting, install any hoops, shadecloth or rowcover and weights.

22. Water the plants well the following day (day 2), and again on days 3,5,7, and 10, if it doesn’t rain well.

23. After that give an inch of water a week, if nature doesn’t. To determine your watering rate, set a vertical-sided empty tuna can or other shallow container in the row while you water (or while it rains).

One of our impact sprinkler tripods, in a broccoli patch.
Photo Pam Dawling

Also see Spring broccoli planting and here.

We aim to plant out our broccoli in the first two weeks ofApril. We may have delays due to wet soil. When we plant late (and big), we sometimes struggle to keep them thriving if the weather is hot. The we have to water a lot, even though the soil was still saturated from the heavy rains.

In those posts you can read about how we mulch our spring broccoli and cabbage planted in temporary raised beds, 4ft (1.2m) wide with one foot (30 cm) paths. We unroll big round bales of spoiled hay over the beds and the paths too. We make two rows of “nests” in each bed, using a measuring stick to get the right spacing. We use our hands to tease the hay apart down to soil level. Then we transplant, water in and close the hay over the soil around the stem of the plant. We cover with rowcover to protect from cold nights, bugs and stiff breezes. We use sticks to hold the rowcover down, rolling the edges under rather than over, which helps them stay in place and not tangle with hoses or feet.

Not much to see – spring broccoli under rowcover.
Photo Kathryn Simmons

Not much to see – spring broccoli under rowcover.
Photo Kathryn Simmons