I'm very new to DnD and tabletops in general. I'm just learning about the game and its rules.

What I want to ask is if it's possible to "precast" a spell? What I mean is; suppose a spell requires a specific amount of time (let's say an hour) and some materials. The spell caster does this after resting and waking up in the morning, then an encounter occurs in the afternoon. Will the spell caster be able to use the spell that they prepared in the morning and use it for this encounter in the afternoon without taking and hour and expending materials? If so, what do they require to do so (some kind of feat?)


You can Ready a spell

There's the ability to Ready a spell, which allows you to cast a spell, but not release its energy yet. You can then specify what kind of thing you are waiting for as a trigger, and use your reaction to cast it when that trigger occurs.

The problem is that this requires your concentration, it has to be a spell with a casting time of one round and its energy can only be held until the start of your next turn. If you have not released the spell yet by then, the spell is wasted.

So while you can "precast" a spell, you can't exactly cast a one-hour casting time spell and then save it for later in the day.

You might count the "Ring of Spell Storing" as another way of precasting a spell, but it simply allows you to cast the spell and touch the ring to store it. The spell states that you can:

While wearing this ring, you can cast any spell stored in it.

Depending on how your DM rules it, you might have to cast the spell again for an hour using the ring, so it won't exactly help in your scenario.

  • \$\begingroup\$ "allows you to cast a spell, but not cast it yet" This is a little oddly phrased. Maybe use the PHB's language of "cast a spell but hold onto its magic and release it later?" \$\endgroup\$ – Rykara Jan 3 at 23:56
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    \$\begingroup\$ It is probably worth clarifying that you cannot ready a spell that does not have a casting time of 1 action. That means that Readying a spell with a casting time of an hour is just not possible. \$\endgroup\$ – Rubiksmoose Jan 4 at 14:03

There are a few ways to encode a spell for later. In these situations, you consume the materials during the storing, but will take the casting time for both storing and unstoring the spells.

  • Spell Scrolls can be made, and the process is spelled out in Xanathar's Guide to Everything. But those are very expensive and take days to complete, and don't benefit from your spellcasting bonuses.
  • A Ring of Spell Storing lets you cast a 1st- through 5th-level spell into the ring and use it at a later date. But this is very rare and you're still using the spell slot to fill the ring.
  • The Glyph of Warding spell has the Spell Glyph feature, where you can cast a spell into the glyph as long as you also cast the Glyph of Warding at the same level or higher. You can then define the trigger that activates the glyph. The downside is that you need to use two spell slots to get one spell, and the glyph can't be moved more than 10 feet, and setting triggers can be complicated and backfire spectacularly.

No, and doing so would lead to serious balance issues. Most spells with long casting times have them specifically because they are very powerful. The only way for this to work is if they took time to prepare and cast the spells in the morning, and then immediately went into the battle, or, at least, did so while the spells were still active.

Consider the spell Prayer of Healing:

Prayer of Healing

2nd-level evocation

Casting Time: 10 minutes Range: 30 feet Components: V Duration: Instantaneous

Up to six creatures of your choice that you can see within range each regain hit points equal to 2d8 + your spellcasting ability modifier. This spell has no effect on undead or constructs. At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the healing increases by 1d8 for each slot level above 2nd.

This spell takes ten minutes to cast specifically because it does a lot of healing to a lot of people, without requiring touch, at a very early level. If castable during combat, every encounter would become incredibly trivial.

Keep in mind that each round in combat is 6 seconds of in-game time. This spell is completely uncastable in combat, and for good reason.

Consider also Conjure Elemental:

Conjure Elemental

5th-level conjuration

Casting Time: 1 minute Range: 90 feet Components: V, S, M (burning incense for air, soft clay for earth, sulfur and phosphorus for fire, or water and sand for water) Duration: Concentration, up to 1 hour

You call forth an elemental servant. Choose an area of air, earth, fire, or water that fills a 10-foot cube within range. An elemental of challenge rating 5 or lower appropriate to the area you chose appears in an unoccupied space within 10 feet of it.

This is marginally more castable in combat, but just barely, requiring 10 full rounds of doing nothing else but summon the elemental. This is because it adds an entire new creature to the field, and lasts for an hour.

So, no, this is not an option. Not with feats, not by default, and it should really not be done by house ruling, because it will very thoroughly break combat if there are any spellcasters present.

However, there is the option to Ready a Spell, but this must be done during combat, and must be a spell that you could feasibly cast on your turn. This is the same as Readying an Action, and means that you specify the spell you wish to cast and the condition under which you will cast it. If that condition does not arise before your next turn, the spell slot is lost, but the spell is not cast. This is the only way to prepare a spell before using it, and only works for one turn in combat.

I believe some of the confusion here may arise from the usage of "prepare" used in the book for certain spellcaster classes. Some caster classes can always use all the spells they know in a certain day; others must pick and choose after each long rest which spells they wish to be able to cast that day. This simply means that the prepared spells are on the list of spells that the caster can use that day; casting times are still the same.

  • \$\begingroup\$ To be fair, the scenarios for the balance concerns don't strike me as being major issues. To cast Prayer of Healing, you could cast it at the time that it's finished (as normal), or with the proposed option to hold it would mean that the caster has to do nothing but holding the spell for several rounds while risking losing the spell to wait until enough damage has been dealt to the party to release it. Additionally, there's not many scenarios where a 1 hour elemental needs to be released in the middle of combat vs. just before combat. \$\endgroup\$ – Daniel Zastoupil Jan 4 at 0:00

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