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Determinate vs. indeterminate tomato plants, and other nagging garden questions answered

  • Author: Jeff Lowenfels
    | Alaska gardening
  • Updated: April 7, 2018
  • Published April 7, 2018

(iStock / Getty Images)

The nagging question of the week, and there are lots of contenders, is this: Can you replant those daffodils and tulips that have been blooming in pots on your dining room table?

Unfortunately, most bulbs forced for indoor blooms do generate a new bulb for next year's growth, which is what bulbs generally do to propagate. This means that once they have finished blooming indoors, you should toss the bulbs and soil onto your compost pile instead of saving them to plant in an outdoor garden. Clean the pot and re-use it or save it for recycling this summer.

Not quite so much a nagger, but a reader asked if she needed to start new parsley plants, as parsley is a biennial. It is true that parsley sets flowers and seeds in its second year, but here in the sub-Arctic, we treat parsley as an annual. It is still a biennial, but it doesn't always make it through our winters. So, the answer is to start new parsley every spring. And, it happens that this is the week to do so. If your plants from last year survived, you will have plenty to give away.

Speaking of biennial plants, what do you do with last year's artichoke plants? These are biennial plants, too, though due to the long summer days, they sometimes flower the first year in Alaska. They will go dormant, however. If you keep them in their containers though the winter next to those fuchsia and in dark storage, they can be brought back to life for the summer. Right about now, you can take yours out and start watering them again.

This is also the time to start new 'chokes. These are big plants that require a lot of room both during the indoor season as well as the outdoor one. However, they are worth it, as they really are a spectacular landscape plant. If you are lucky, you may get a few edible flowers.

Next, a reader wants advice regarding the choice between determinate and indeterminate tomato plants. This is an important question, especially since now is the time to get tomatoes growing.

Determinate tomato plants are also known as "bush tomatoes," as they reach a certain height and stop growing upward. They put out side shots, however. Determinate tomato seeds grow into relatively compact and bushy plants.

Indeterminate tomato plants, on the other hand, continue to get taller throughout the season and only stop growing when it gets too cold. I have seen some plants that were 18 feet "tall," though they were actually laid down on the greenhouse benches. Fortunately, you can prune indeterminate plants back to whatever size you want. As you can imagine, indeterminate plants need a lot more staking than determinate plants.

As significant, determinate tomato plants produce all their fruit at about the same time, say within a two-week period. After this one flush of flowers, they are finished for the season. Indeterminate plants, on the other hand, produce flowers all through the season once they reach maturity. Continuous blossoms means a continuous supply of fruit throughout the season.

Both types produce the exact same, tasty fruit; Once harvested, you can't tell what type of plant produced which tomatoes. So, the choice is yours, based on when you want to harvest and how much space you have in your outdoor greenhouse. In case you can't decide, there are some semi-determinate plants, but I don't want to confuse things. Just check the packages of seed to make sure you know what you are growing so you can prepare for harvest and for staking.

Finally, what is all the "pinching a plant" stuff all about?

If you grow seedlings indoors, you need to know about pinching. That is because some plants will grow two lead tips when one is pinched off. Doing it a few times early in a plant's life causes the plant to bush out. This produces not only a better-looking plant, but flowers generally come from growing tips and the more tips, the more flowers.

The question is really, which plants to pinch? To know, look at your seedlings, and see if new leaves develop exactly opposite from each other (that is, symmetrical), or offset from each other (asymmetrical). The general rule is that the symmetrical plants should be pinched because two new branches will immediate be produced in the place of each taken off. These are the plants that will bush up.

Hopefully, this will be the last week of snow in most Alaskan yards. Buds are swelling and it is time to start looking for the returning geese.

Jeff's Alaska garden calendar

Seed-starting workshop: 6-7:30 p.m., April 12, at the Alaska Botanical Garden. There's a discount fee for members. See for details.

Bring bird feeders in!: In case you have not heard, the bruins are back and they are looking for some nice fat, which is what your sunflower seeds represent to them. Feeders and containers of seed need to be put where bears will not get them. NOW.

Herbs to start from seed: Sorrel, summer savory and parsley. Is cannabis an herb? It needs to be started now, too.

Vegetables to start from seed: Head lettuces, cabbage, kale, peppers, tomatoes, broccoli and cauliflower

Flowers to start from seed: Dianthus, larkspur, stock, asters, nicotiana, cleome, annual ice plant, zinnia, salpiglossis, snaps, cosmos, lupine, Malva and cannabis.

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